Specifications for the
QUALANOD Quality Label
for Sulfuric Acid-Based Anodizing of
Aluminium
Edition
01.01.2017
EFFECTIVE FROM 1 January 2017
This edition supersedes the previous edition (01.07.2010) and
may be supplemented with new update sheets.
All current update sheets are published on the Internet: www.qualanod.net
TUTUTUTU
UUUUTTTT
OFFICIAL VERSION PRINTED BY QUALANOD
Josef Schoppig
Mailing address:
QUALANOD, PO. Box 1507, CH-8027 Zurich
Domicile:
QUALANOD c/o AC-Fiduciaire SA (certification body)
Tödistrasse 47, CH-8002 Zurich
Phone:
+41 (0)43 305 09 70
Fax:
+41 (0)43 305 09 98
E-Mail: [email protected]
Internet:
www.qualanod.net
CONTENTS
CONTENTS .......................................................................................................................... 2
Introduction.................................................................................................................. 5
Scope............................................................................................................................ 5
Language...................................................................................................................... 6
References ................................................................................................................... 6
Terms and definitions.................................................................................................. 8
Licensing anodizers................................................................................................... 10
6.1
General................................................................................................................. 10
6.2
Granting a licence................................................................................................. 10
6.3
Renewing a licence............................................................................................... 12
6.4
Withdrawal of a licence ......................................................................................... 13
6.5
Change to the licensable products of a licence ..................................................... 14
Regulations for the use of the quality label ............................................................. 15
7.1
Ownership of the quality label ............................................................................... 15
7.2
Register of licence holders.................................................................................... 15
7.3
Qualifications of applicant ..................................................................................... 15
7.4
Products covered by the licence ........................................................................... 15
7.5
Use of the quality label by licence holders ............................................................ 15
7.6
Communications ................................................................................................... 17
Inspections................................................................................................................. 18
8.1
General................................................................................................................. 18
8.2
Scope of the inspections....................................................................................... 18
8.3
Inspection of products........................................................................................... 18
8.4
Inspection of processes ........................................................................................ 21
Test methods for products........................................................................................ 22
9.1
General................................................................................................................. 22
9.2
Measurement of thickness .................................................................................... 22
9.3
Sealing tests ......................................................................................................... 22
9.4
Appearance .......................................................................................................... 23
9.5
Corrosion resistance ............................................................................................. 24
9.6
Resistance to wear / abrasion ............................................................................... 24
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9.7
Microhardness ...................................................................................................... 26
9.8
Resistance to cracking by deformation.................................................................. 26
9.9
Fastness to light and ultraviolet radiation .............................................................. 27
9.10
Electrical breakdown potential .............................................................................. 27
9.11
Coating continuity ................................................................................................. 27
9.12
Surface density ..................................................................................................... 27
9.13
Thermal craze resistance...................................................................................... 27
9.14
Summary of product tests for the different types of anodizing ............................... 28
Approval of new processes and products ............................................................... 29
Guidance on products and processes ..................................................................... 30
11.1
General................................................................................................................. 30
11.2
The aluminium to be anodized .............................................................................. 30
11.3
Anodic oxidation coating thickness ....................................................................... 32
11.4
Appearance .......................................................................................................... 32
11.5
Equipment of anodizing plants .............................................................................. 33
11.6
Processes of anodizing plants .............................................................................. 35
11.7
Cleaning and maintenance ................................................................................... 39
Appendix – Architectural anodizing ......................................................................... 41
12.1
Introduction........................................................................................................... 41
12.2
Scope ................................................................................................................... 41
12.3
Quality label .......................................................................................................... 41
12.4
Agreements with customers.................................................................................. 41
12.5
Complaints............................................................................................................ 42
12.6
Laboratory and testing apparatus.......................................................................... 42
12.7
Product tests to be applied by the licensee ........................................................... 43
12.8
Requirements concerning processes .................................................................... 45
12.9
Methods for process control.................................................................................. 46
12.10 Production control records .................................................................................... 48
12.11 Inspections ........................................................................................................... 48
Appendix - Industrial anodizing................................................................................ 50
13.1
Introduction........................................................................................................... 50
13.2
Scope ................................................................................................................... 50
13.3
Quality label .......................................................................................................... 50
13.4
Agreements with customers.................................................................................. 50
13.5
Complaints............................................................................................................ 51
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13.6
Laboratory and testing apparatus.......................................................................... 52
13.7
Product tests to be applied by the licensee ........................................................... 52
13.8
Requirements concerning processes .................................................................... 55
13.9
Methods for process control.................................................................................. 56
13.10 Production control records .................................................................................... 57
13.11 Inspections ........................................................................................................... 58
Appendix - Decorative anodizing.............................................................................. 60
14.1
Introduction........................................................................................................... 60
14.2
Scope ................................................................................................................... 60
14.3
Quality label .......................................................................................................... 60
14.4
Agreements with customers.................................................................................. 60
14.5
Complaints............................................................................................................ 61
14.6
Laboratory and testing apparatus.......................................................................... 61
14.7
Product tests to be applied by the licensee ........................................................... 62
14.8
Requirements concerning processes .................................................................... 64
14.9
Methods for process control.................................................................................. 65
14.10 Production control records .................................................................................... 66
14.11 Inspections ........................................................................................................... 67
Appendix - Hard anodizing........................................................................................ 69
15.1
Introduction........................................................................................................... 69
15.2
Scope ................................................................................................................... 69
15.3
Quality label .......................................................................................................... 69
15.4
Agreements with customers.................................................................................. 69
15.5
Complaints............................................................................................................ 70
15.6
Laboratory and testing apparatus.......................................................................... 70
15.7
Product tests to be applied by the licensee ........................................................... 70
15.8
Requirements concerning processes .................................................................... 72
15.9
Methods for process control.................................................................................. 72
15.10 Production control records .................................................................................... 73
15.11 Inspections ........................................................................................................... 73
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Introduction
Qualanod is a quality label organisation founded in 1974 by several national associations
encompassing architectural anodizers in the European Anodizers Association (EURAS), and
in conjunction with the European Wrought Aluminium Association (EWAA). EWAA was
succeeded by the European Aluminium Association (EAA) in 1982 while EURAS was
succeeded by European Surface Treatment on Aluminium (ESTAL) in 1994. In 2004, the
scope of Qualanod was extended to include sulfuric acid anodizing of aluminium for other
applications.
Qualanod is committed to maintaining and promoting the quality of anodized aluminium.
These Specifications cover requirements strictly to be followed by licensees and prospective
licensees, and recommendations for licensees. They also provide relevant information for
licensees of actions by general licence holders, testing institutes, inspectors and Qualanod.
General licence holders are permitted by Qualanod to license anodizing plants to use the
Qualanod quality label. The general licence holders also regulate the testing institutes.
These Specifications conform to ISO 7599, a method of specifying for decorative and
protective anodizing including architectural anodizing, except where otherwise stated, and
also include requirements of ISO 10074, a specification for hard anodizing.
These Specifications are divided into clauses and have a series of appendices. Clauses cover
general requirements that apply to any licensee and include the processes of licensing,
inspections, the use of the quality label and requirements for product performance tests.
Guidance and recommendations on products and processes are also covered in these
Specifications.
Each appendix defines a specific type of anodizing (see also clause 5) and gives the
associated requirements to conform to these Specifications. The appendices are:
• architectural anodizing
• industrial anodizing
• decorative anodizing
• hard anodizing
In order to find out how to comply with the requirements of these Specifications, a licensee
should refer to the relevant appendices depending on the licensable products set out in its
licence.
Scope
These Specifications specify requirements for sulfuric acid anodizing and products produced
by sulfuric acid anodizing.
Sulfuric acid anodizing is defined in ISO 7583 as anodizing in an electrolyte based on sulfuric
acid.
These Specifications are not applicable to:
• anodizing in the production of lithographic plates;
• anodizing used as a pretreatment before the application of a powder coating, a paint
or an adhesive;
• anodizing in the production of a combined coating.
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Language
The official version of these Specifications is the English language version.
In the English language version, certain verbal forms have particular meanings which
correspond to the requirements of the ISO/IEC Directives, Part 2, Annex H.
The following verbal forms indicate requirements strictly to be followed in order to comply with
these Specifications and from which no deviation is permitted.
shall
shall not
The following verbal forms indicate that among several possibilities one is recommended as
particularly suitable, without mentioning or excluding others, or that a certain course of action
is preferred but not necessarily required, or that (in the negative form) a certain possibility or
course of action is deprecated but not prohibited.
should
should not
The following verbal forms indicate a course of action permissible within the limits of these
Specifications.
may
need not
The following verbal forms are used for statements of possibility and capability, whether
material, physical or causal.
can
cannot
References
The following referenced documents can be important for the application of these
Specifications. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 485-1, Aluminium and aluminium alloys -- Sheet, strip and plate -- Technical conditions for
inspection and delivery
EN 573-3, Aluminium and aluminium alloys -- Chemical composition and form of wrought
products -- Chemical composition and form of products
EN 586-1, Aluminium and aluminium alloys – Forgings -- Technical conditions for inspection
and delivery
EN 754-1, Aluminium and aluminium alloys -- Cold drawn rod/bar and tube -- Technical
conditions for inspection and delivery
EN 755-1, Aluminium and aluminium alloys -- Extruded rod/bar, tube and profiles -- Technical
conditions for inspection and delivery
EN 1090-1: 2009 + A1: 2011, Execution of steel structures and aluminium structures Part 1:
Requirements for conformity assessment of structural components
EN 12020-1, Aluminium and aluminium alloys -- Extruded precision profiles in alloys EN AW6060 and EN AW-6063 -- Technical conditions for inspection and delivery
EN 1999-1-1, Eurocode 9 -- Design of aluminium structures -- General structural rules
ISO 1463, Metallic and oxide coatings — Measurement of coating thickness — Microscopical
method
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ISO 2085, Anodizing of aluminium and its alloys -- Check for continuity of thin anodic oxidation
coatings -- Copper sulfate test
ISO 2106, Anodizing of aluminium and its alloys -- Determination of mass per unit area
(surface density) of anodic oxidation coatings -- Gravimetric method
ISO 2128, Anodizing of aluminium and its alloys — Determination of thickness of anodic
oxidation coatings — Non-destructive measurement by split-beam microscope
ISO 2135, Anodizing of aluminium and its alloys -- Accelerated test of light fastness of coloured
anodic oxidation coatings using artificial light
ISO 2143, Anodizing of aluminium and its alloys — Estimation of loss of absorptive power of
anodic oxidation coatings after sealing — Dye-spot test with prior acid treatment
ISO 2360, Non-conductive coatings on non-magnetic electrically conductive basis materials
— Measurement of coating thickness — Amplitude-sensitive eddy-current method
ISO 2376, Anodizing of aluminium and its alloys -- Determination of electric breakdown
potential
ISO 2931, Anodizing of aluminium and its alloys — Assessment of quality of sealed anodic
oxidation coatings by measurement of admittance
ISO 3210, Anodizing of aluminium and its alloys -- Assessment of quality of sealed anodic
oxidation coatings by measurement of the loss of mass after immersion in phosphoric
acid/chromic acid solution
ISO 3211, Anodizing of aluminium and its alloys -- Assessment of resistance of anodic
oxidation coatings to cracking by deformation
ISO 4516, Metallic and other inorganic coatings -- Vickers and Knoop microhardness tests
ISO 6362-1, Wrought aluminium and aluminium alloys -- Extruded rods/bars, tubes and
profiles -- Technical conditions for inspection and delivery
ISO 6581, Anodizing of aluminium and its alloys -- Determination of the comparative fastness
to ultraviolet light and heat of coloured anodic oxidation coatings
ISO 6719, Anodizing of aluminium and its alloys -- Measurement of reflectance characteristics
of aluminium surfaces using integrating-sphere instruments
ISO 7583, Anodizing of aluminium and its alloys — Terms and definitions
ISO 7599:2010, Anodizing of aluminium and its alloys -- General specifications for anodic
oxidation coatings on aluminium
ISO 7668, Anodizing of aluminium and its alloys -- Measurement of specular reflectance and
specular gloss of anodic oxidation coatings at angles of 20 degrees, 45 degrees, 60 degrees
or 85 degrees
ISO 8251, Anodizing of aluminium and its alloys -- Measurement of abrasion resistance of
anodic oxidation coatings
ISO 8993, Anodizing of aluminium and its alloys -- Rating system for the evaluation of pitting
corrosion -- Chart method
ISO 8994, Anodizing of aluminium and its alloys -- Rating system for the evaluation of pitting
corrosion -- Grid method
ISO 9227, Corrosion tests in artificial atmospheres -- Salt spray tests
ISO 10074, Anodizing of aluminium and its alloys -- Specification for hard anodic oxidation
coatings on aluminium and its alloys
ISO 10215, Anodizing of aluminium and its alloys -- Visual determination of image clarity of
anodic oxidation coatings -- Chart scale method
ISO 10216, Anodizing of aluminium and its alloys -- Instrumental determination of image clarity
of anodic oxidation coatings -- Instrumental method
ISO 11664, Colorimetry
ISO/IEC 17025, General requirements for the competence of testing and calibration
laboratories
ISO/IEC 17065, Conformity assessment -- Requirements for bodies certifying products,
processes and services
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Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7583 and the
following apply.
5.1
architectural anodizing
anodizing to produce an architectural finish to be used in permanent, exterior and static
situations where both appearance and long life are important
5.2
decorative anodizing
anodizing to produce a decorative finish with a uniform or aesthetically pleasing appearance
as the primary characteristic
5.3
general licence holder
general licensee
GL
organization that may grant Qualanod sub-licences to anodizing plants
Note: Such organizations include national associations and Qualanod.
5.4
hard anodizing
anodizing to produce a coating where high wear resistance or microhardness is its primary
characteristic
5.5
industrial anodizing
anodizing to produce a functional finish where appearance is secondary or of no importance
5.6
licensable product
product type, as described in the Regulations, for which the sub-licensee may use the quality
label
5.7
lot
articles of the same alloy and temper which comprise a customer's order or the part of it that
is in the plant
5.8
lot acceptance test
test on a production lot to determine its conformance to the requirements of these
Specifications
5.9
Qualanod
Association for Quality Control in the Anodizing Industry, Zurich
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5.10
quality label
label
design including the trademark owned by the Association for Quality Control in the Anodizing
Industry (Qualanod), Zurich and first registered on 16 August 1974 in the International
Register by the World Intellectual Property Organization (WIPO) – registration number
409951.
Note 1: Examples of the quality label are shown in clause 7.
Note 2: The registration was renewed on 16 August 2014 for a period of ten years.
5.11
Regulations
regulations for the use of the Qualanod quality label for sulfuric acid anodizing of aluminium
5.12
Specifications
specifications for the quality label for sulfuric acid anodizing of aluminium issued from time to
time by Qualanod.
5.13
sub-licence
licence
statement issued by or in the name of QUANALOD authorizing the use of the quality label
according to the current Regulations
5.14
sub-licence holder
licence holder
holder
licensee
anodizing plant authorized to use the quality label
5.15
testing institute
testing laboratory
organization that is accredited under ISO/IEC 17025 for the tests stipulated by QUALANOD
and mandated by a general licensee to be responsible for inspecting the anodizing plants of
licensees
Note: Inspectors are nominated by testing institutes or by general licensees accredited to
ISO/IEC 17065
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Licensing anodizers
6.1 General
This clause gives general information on the roles of the inspector, the testing institute, the
general licensee and Qualanod. It includes actions required of the licensee or prospective
licensee.
6.1.1 Licensable products
A Qualanod licence specifies the licensable products for which the anodizing plant may use
the label. Those products are identified by reference to the appendices of these
Specifications. The appendices are:
•
•
•
•
architectural anodizing
industrial anodizing
decorative anodizing
hard anodizing
The Qualanod secretariat issues licence certificates which identify the licensable products.
6.1.2 Inspections
In order to renew or be granted a Qualanod licence, an anodizing plant is inspected to
determine conformity to these Specifications. At an inspection visit, the inspector undertakes
inspections for each licensable product for which the anodizing plant wants to use the label.
Note that the inspection visit can be fully satisfactory or fully unsatisfactory, or partially
satisfactory if it is satisfactory for some of those licensable products but not for others.
All information concerning inspection results and their assessment is confidential.
6.1.3 Appeals
If the general licensee decides that an inspection of an anodizing plant is not fully satisfactory,
the plant is entitled to appeal to the general licensee. The plant shall submit its appeal within
ten days of receiving the notification of the decision from the general licensee. If the plant is
not satisfied with the result of the appeal, it may appeal to Qualanod. Qualanod’s decision is
final.
6.2 Granting a licence
6.2.1 Application
If an anodizing plant not holding a Qualanod licence wants to apply for a Qualanod licence, it
shall make a written application to a general licensee.
The general licensee is normally the appropriate national association but may be another
organization with the authority to grant a licence. The general licensee designates the testing
institute responsible for inspections or, if it is accredited to ISO/IEC 17065, it may nominate
the inspector itself.
The anodizing plant and the general licensee agree the licensable products for which the
anodizing plant seeks to use the label.
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If an anodizing plant already holding a Qualanod licence wants to use the label for one or
more additional licensable products, it shall make a written application to a general licensee.
It then undergoes the procedure described below for granting a licence.
6.2.2 Inspections
Inspections of anodizing plants are carried out according to the scheme shown in diagram A.
No more than four inspections for each licensable product are permitted before the decision
on licensing is made. If an anodizing plant seeks a licence for more than one licensable
product, then an inspection visit can include all of those licensable products. It is not
necessary for each licensable product to be dealt with at a separate visit to the plant.
The date of the first inspection visit is agreed to ensure that the responsible persons of the
anodizing plant are present in the plant. Subsequent inspection visits are carried out
unannounced unless other arrangements are approved by Qualanod.
The inspector records the results of each inspection visit on the inspection report form
provided by Qualanod. At the end of the inspection visit, a form summarizing the remarks of
the inspector is signed by both the inspector and the anodizing plant which may add
comments. Subsequently, the inspection report is submitted to the general licensee.
6.2.3 Assessment of the results of inspections
The general licensee assesses the results in the inspection report and decides whether the
results are satisfactory. It can consult Qualanod for guidance in reaching its decision.
Following its decision, the general licensee sends to the anodizing plant:
1. a copy of the inspection report;
2. notification of the decision;
3. if the results of the inspection visit are not deemed fully satisfactory, a full explanation for
the conclusion.
Diagram A. Inspection procedure for each licensable product
After an unsatisfactory or partially satisfactory inspection visit where plant and/or equipment
did not meet the requirements, another inspection visit can be made only when the anodizing
plant has given notification to the general licensee that it has rectified the deficiencies
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recorded. The general licensee informs the testing institute of the receipt of the notification
or, if it is accredited to ISO/IEC 17065, it informs the inspector.
After an unsatisfactory or partially satisfactory inspection visit, the anodizing plant may
withdraw its application for a licence for one or more licensable products. In such
circumstances, it shall notify the general licensee by written communication. The general
licensee informs the testing institute or, if it is accredited to ISO/IEC 17065, it informs the
inspector.
6.2.4 Licensing
A general licensee can grant a licence to an anodizing plant if at least two inspections are
satisfactory for each licensable product for which the plant seeks to use the label. If a licence
is granted, the general licensee and the anodizing plant sign the contract provided by
Qualanod.
If a licence cannot be granted, the anodizing plant shall not make a new application for a
licence until at least six months have elapsed. If a licence cannot be granted for a licensable
product, the anodizing plant shall not make a new application for a licence for that licensable
product until at least six months have elapsed.
6.3 Renewing a licence
6.3.1 Application
The general licensee initiates the renewal process.
If an anodizing plant does not want its licence renewed for one of more licensable products, it
shall inform the general licensee by written communication.
6.3.2 Routine inspections
Inspections of anodizing plants are carried out according to the scheme shown in diagram A.
No more than four inspections for each licensable product are permitted per calendar year
before the decision on licensing is made. If an anodizing plant seeks to renew its licence for
more than one licensable product, then an inspection visit can include all of those licensable
products. It is not necessary for each licensable product to be dealt with at a separate
visit to the plant.
The inspections are carried out unannounced unless other arrangements are approved by
Qualanod.
The inspector records the results of each inspection visit on the inspection report form
provided by Qualanod. At the end of the inspection visit, a form summarizing the remarks of
the inspector is signed by both the inspector and the anodizing plant which may add
comments. Subsequently, the inspection report is submitted to the general licensee.
6.3.3 Assessment of the results of inspections
The general licensee assesses the results in the inspection report and decides whether the
results are satisfactory. It can consult Qualanod for guidance in reaching its decision.
Following its decision, the general licensee sends to the anodizing plant:
1. a copy of the inspection report;
2. notification of the decision;
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3. if the results of the inspection visit are not deemed fully satisfactory, a full explanation for
the conclusion.
After an unsatisfactory or partially satisfactory routine inspection visit, a repeat inspection visit
is carried out within one month of the anodizing plant receiving from the general licensee
notification that the inspection was not fully satisfactory. However, if plant and/or equipment
did not meet the requirements, another inspection visit can be made only when the anodizing
plant has given notification to the general licensee that it has rectified the deficiencies
recorded. The general licensee informs the testing institute of the receipt of the notification
or, if it is accredited to ISO/IEC 17065, it informs the inspector.
After an unsatisfactory or partially unsatisfactory inspection visit, the anodizing plant may
decide that it does not want its licence renewed for one or more licensable products. In such
circumstances, it shall notify the general licensee by written communication. The general
licensee informs the testing institute or, if it is accredited to ISO/IEC 17065, it informs the
inspector.
6.3.4 Licensing
A general licensee can renew a sub-licence of an anodizing plant if at least two inspections
per calendar year are satisfactory for each licensable product for which the plant seeks to use
the label. In other circumstances the executive committee of Qualanod or the general
licensee, if it is accredited to ISO/IEC 17065, decides.
If a licence cannot be renewed, the anodizing plant shall not make a new application for a
licence until at least six months have elapsed. If a licence cannot be renewed for a licensable
product, the anodizing plant shall not make a new application for a licence for that licensable
product until at least six months have elapsed.
6.4 Withdrawal of a licence
The general licensee withdraws the licence if the holder no longer complies with the
Regulations and, in particular, in the event of any unauthorized or incorrect use of the quality
label.
If, as described above, the licence of an anodizing plant cannot be renewed, the general
licensee can withdraw the licence.
In the case of unforeseen circumstances and, if appropriate, after consultation with the
responsible testing institute, inspections can be suspended for a maximum period of 12
months from the moment when the general licensee is informed that circumstances have
prevented an inspection from being carried out. After this period, the licence is withdrawn.
If the general licensee withdraws the licence from an anodizing plant, it notifies the plant
immediately in writing. The withdrawal has effect from the date of receipt of the notification.
If a licence is withdrawn or if the licensee ceases to trade, all tags, labels, bands, stencils,
stamps, sleeves, containers, price lists, business notices, business cards and any other
objects in or on which the quality label is shown shall be either given to the general licensee
or, on the instructions of the latter, kept at the disposal of the general licensee until application
for a new licence is made by the legal representatives or successors in business of the
previous licence holder. The previous licence is deemed withdrawn until issue of the new
licence. However, the legal representatives or successors in business of the previous licence
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holder are entitled to continue to use the quality label for three months pending the grant of a
new licence unless the general licensee issues instructions to the contrary.
If a licence is withdrawn, the anodizing plant shall not make a new application for a licence
until at least six months have elapsed.
All licence holders shall respect relevant national laws in the conduct of their operations. If a
licence holder is proven not do so, Qualanod can withdraw the licence (to protect Qualanod’s
image and/or for fair trade principles).
6.5 Change to the licensable products of a licence
If, as described above, the licence of an anodizing plant cannot be renewed for certain
licensable products, the general licensee can change the licensable products of the licence.
If the general licensee changes the licensable products of a licence, it notifies the plant
immediately in writing. The change has effect from the date of receipt of the notification.
If the licensable products of a licence are changed, the licensee shall not use the quality label
in conjunction with any products that are no longer covered by the licence.
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Regulations for the use of the quality label
7.1 Ownership of the quality label
The trademark included in the quality label is owned by Qualanod and shall not be adopted
by anyone unless authorized to do so. Anodizing plants can be authorized to use the quality
label by a licence granted according to these Regulations.
Qualanod grants a general licence for the quality label to a general licensee with powers to
authorize use of the label to individual anodizing plants according to the present Regulations.
7.2 Register of licence holders
Qualanod keeps a register which (in addition to other details which can be resolved now or
later) shows name, address and trade description of each licence holder, the date on which
the licence was granted to the licence holder, the number assigned to each licence holder, the
date of withdrawal of the licence and any other details which Qualanod deems necessary.
The licence holder shall notify the general licensee without delay of any changes in name or
address. The latter passes the information to Qualanod for the amendment of the appropriate
entry in the register.
7.3 Qualifications of applicant
Authorization to use the quality label is granted on condition that the applicant conducts, or
intends to conduct an anodizing business which actually supplies products covered by the
licence.
7.4 Products covered by the licence
The quality label shall be used only for sulfuric acid anodizing of aluminium which conforms to
these Specifications.
Grant of a licence entitles the licence holder to use the quality label only for the licensable
products set out in its licence. The licence specifies those products by reference to the
appendices of these Specifications. The licence is not transferable. The appendices are:
• architectural anodizing
• industrial anodizing
• decorative anodizing
• hard anodizing
A licensee shall not sub-contract the whole or a part of a customer’s order for licensable
products set out in its licence to another plant unless it is also a licensee authorized to produce
such products.
7.5 Use of the quality label by licence holders
The quality label shall be used either in black and white or in blue and white. It may be used
on the goods themselves, on business stationery, quotations or invoices, price lists, cards,
display cards and on all company literature, brochures, catalogues and in newspaper
advertisements. The words "Quality Label for Anodizing of Aluminium” (or some other text
conforming to national legislation) may be added in the space to the right (Figure 1a and 1b).
By the use of the label on a product, the licensee guarantees that the quality supplied conforms
to the quality offered or, as appropriate, the quality ordered.
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Figure 1. The use of the quality label
a) These may be used on stationery, company literature, catalogues etc. as well as on
newspaper advertisements.
b) If the thickness class is specified, it shall be included on the label if stamped on goods
and packaging; also on invoices and accompanying papers referring to a particular
consignment unless the thickness class has already been indicated in those documents.
c) This may be stamped or printed directly on adhesive tapes or stickers.
If the thickness class is specified, it shall be:
−
printed in the symbol when the quality label is stamped on goods and packaging;
−
given in writing on invoices and accompanying papers referring to a particular
consignment unless the thickness class has already been indicated in these
documents.
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If a licence holder has several anodizing plants, the quality label shall only be used on the
goods themselves and on packaging. This restriction does not apply if each plant belonging
to the licence holder is licensed to use the quality label for the products concerned.
The quality label, inner motif 25 x 25 mm, may be stamped or printed directly onto adhesive
tape or stickers (Figure 1c) in the above-mentioned colours.
The holder shall not make any alteration or addition to the quality label when using it. In the
event of the separate use of the holder's own brand or trade marks on, or in connection with
his products, these requirements shall not be contravened.
The holder shall, at all times, give the general licensee any information required with respect
to his use of the quality label.
7.6 Communications
Any communication from the holder required to be made under these Regulations shall be
effective if made by a correctly stamped and addressed letter or email. Cancellation of licences
is disseminated by registered mail.
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Inspections
8.1 General
The aim of an inspection is to verify that the licensee is in compliance with the requirements
of these Specifications for the products set out in its licence. The requirements depend on the
type of anodizing and are described in the appendices of these Specifications.
Another aim of an inspection is to verify that the licensee does not associate the quality label
with unlicensed products.
Each inspection is the responsibility of the testing institute designated by the general licensee
or of the general licensee if it is accredited to ISO/IEC 17065. The testing institute or the
accredited general licensee nominates a suitably qualified individual who has been approved
by Qualanod, referred to as the inspector, to carry out the inspection.
8.2 Scope of the inspections
The inspector determines from the anodizing plant’s licence what products it is licensed to
produce. The relevant appendix or appendices of these Specifications informs the inspector
of the product tests to be performed during the inspection. The appendices are:
• architectural anodizing
• industrial anodizing
• decorative anodizing
• hard anodizing
8.3 Inspection of products
8.3.1 General
Although this sub-clause is written as if the inspector carries out all the tests himself,
alternatively he can require appropriate plant personnel to carry out tests under his
supervision. Thus, he is able to verify that the test is performed correctly.
The inspector can remove samples from anodizing plant for the tests to be carried out at the
testing institute.
The inspector verifies that the licensee has copies of the standards specifying the tests that it
carries out.
8.3.2 Use of the quality label
The inspector verifies that the use of the quality label complies with the requirements of clause
7.
8.3.3 Agreements with customers
The inspector verifies that agreements with customers conform to the requirements set out in
the subclauses “Agreements with customers” in the appendices.
8.3.4 Laboratory
The inspector verifies that the laboratory and testing apparatus conform to the requirements
set out in the subclauses “Laboratory and testing apparatus” in the appendices.
If the licensee performs the manual surface abrasion test, the inspector carries out validation
tests on the licensee’s glass-coated abrasive paper.
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8.3.5 Test pieces
The inspector carries out tests only on finished products which the anodizing plant has
inspected and passed as satisfactory or on parts which have been packed and/or are ready
for dispatch. A welded frame is considered to be one test piece. Each part of a frame that
has been mechanically screwed together comprises one test piece. Constructions joined
together by heat-insulating, nonconductive material are taken to comprise separate test
pieces.
The anodizing plant shall indicate to the inspector which goods have passed the internal
quality control and by which type of anodizing they were produced.
If it is not possible to take and test specimens from the production lot because of the shape,
size or form of the product, the inspector can carry out the tests on panels made of the same
alloy as the production lot and treated simultaneously with it.
The inspector does not carry out tests on finished products that are not covered by the
anodizing plant’s licence. Such parts shall be clearly identified. The inspector can seek
verification of the type of anodizing by, for example, examining the written agreement between
the anodizing plant and its customer.
8.3.6 Thickness measurement
The anodic oxidation coating thickness is specified as either a thickness class or as a nominal
thickness depending on the type of anodizing. The inspector ascertains the thickness class
or nominal thickness required by the customer by reference to the subclauses “Agreements
with customers” in the appendices. He measures the coating thickness of finished products
using the method of ISO 2360. He follows the procedures of ISO 7599.
It is important that sufficient material is available for the tests. It is recommended that the
amount should be equivalent to at least half a shift’s production. That includes all the types of
anodizing covered by the plant’s licence. In order to avoid an unproductive inspection visit, it
is advisable that the plant notifies the appropriate body if it is concerned that sufficient material
might not be available during certain periods.
The inspector checks all sheet and strip pieces with a significant surface greater than 2 m².
Where a thickness class is specified, no piece shall have an average thickness or local
thickness less than the minimum required for the thickness class. Where a nominal thickness
of up to 50 µm is specified, no piece shall have an average thickness outside ± 20% of the
nominal thickness. Where a nominal thickness over 50 µm is specified, no piece shall have
an average thickness outside ± 10 µm of the nominal thickness.
For other parts, the inspector applies statistical control on samples taken according to Table
1. He always checks at least 30 parts for each type of anodizing. Where a thickness class is
specified, Table 1 gives the maximum number of samples which may each have an average
thickness less than the minimum required for the thickness class. Where a thickness class is
specified, no measured sample shall have a local thickness less than the minimum required
for the thickness class. Where a nominal thickness of up to 50 µm is specified, Table 1 gives
the maximum number of samples which may each have an average thickness outside ± 20%
of the nominal thickness. Where a nominal thickness over 50 µm is specified, Table 1 gives
the maximum number of samples which may each have an average thickness outside ± 10
µm of the nominal thickness.
Note that the minimum local thickness is 80% of the minimum average thickness required for
that thickness class.
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Table 1. Requirements for sampling different lot sizes
Lot size
Number of randomlyselected samples
Acceptable number of
sub-standard samples
1 to 10
all
0
11 to 200
201 to 300
301 to 500
501 to 800
801 to 1300
1301 to 3200
3201 to 8000
8001 to 22000
22001 to 110000
10
15
20
30
40
55
75
115
150
1
1
2
3
3
4
6
8
11
8.3.7 Mass loss test
The inspector carries out mass loss tests as described in the subclauses “Product tests carried
out during an inspection” in the appendices. The samples are taken from sections that have
already been tested and prepared by the licensee as instructed by the inspector.
If the lots inspected include more than one type of anodizing and/or both clear and colour
anodized aluminium, then one mass loss test is carried on a sample from the lot that could
have the most demanding sealing requirements. Thus, the test is carried out on a colouranodized sample rather than a clear-anodized sample. The test is carried out with prior acid
treatment rather than without prior acid treatment.
When a lot is inspected, if admittance measurements are made, the mass loss test is
performed on the part from the sample with the highest admittance. If cold sealing is used,
the mass loss test is performed on the part from the sample with the highest thickness value.
If, during the inspection, the inspector finds a mass loss greater than the acceptance limit, he
repeats the test with a new sample taken from the same part.
If the test is performed at the testing institute, the inspector takes from the anodizing plant two
samples from each part. The test is carried out not more than 2 weeks after sealing.
If both samples from any one part give mass losses greater than the acceptance limit, then
the inspection is deemed to be unsatisfactory.
8.3.8 Dye spot and admittance tests
The inspector carries out the dye spot test or the admittance test as described in the
subclauses “Product tests carried out during an inspection” in the appendices.
The rules on sampling are the same as for thickness measurements (see above) except that
all the samples tested shall satisfy acceptance requirements of the test.
8.3.9 Surface abrasion resistance test
The inspector carries out the surface abrasion resistance test as described in the subclauses
“Product tests carried out during an inspection” in the appendices.
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If the samples taken for statistical control (see above) include samples of thickness classes
AA 20 or thicker, the inspector performs the surface abrasion resistance test on the sample
with the highest thickness.
8.3.10 In-house control
The inspector verifies that the in-house control conforms to the requirements set out in the
subclauses “Production control records” in the appendices, and includes the required product
test data and process control data set out in subclauses “Product tests to be applied by the
licensee” and “Methods for process control” respectively in the appendices.
8.3.11 Register of complaints
The inspector verifies that a register of complaints has been maintained and adequately
describes how complaints have been investigated and actions completed.
8.4 Inspection of processes
The inspector verifies that the processes are carried out in compliance with the requirements
set out in the subclauses “Processes” in the appendices. He also verifies by observation that
bath analyses are performed correctly.
If a licensee does not want a particular anodizing line to be included in the inspection, he shall
provide evidence to the inspector that it is not used for products covered by his licence.
Production control records can provide such evidence.
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Test methods for products
9.1 General
Every acceptance test shall be carried out as specified in these Specifications. In cases of
dispute, the appropriate referee test specified in these Specifications shall be used.
If no method is specified in these Specifications, the test shall be carried out as specified by
the customer.
Unless it is specified as a required test in subclauses “Product tests to be applied by the
licensee” in the appendices, any test for production control purposes shall be adopted at the
discretion of the licensee.
9.2 Measurement of thickness
Coating thickness shall be measured using one or more of the methods identified in ISO 7599.
The method specified in ISO 2360 (eddy current) is the usual method. In cases of dispute,
the method specified in ISO 1463 or ISO 9220 (micro-section) shall be the referee method.
Average or local thickness or both shall be determined from thickness measurements by
following the procedures set out in ISO 7599. Nominal thickness may also be determined by
following the procedures set out in ISO 7599.
The measurements shall be made on the significant surfaces but not within 5 mm of contact
marks or close to a sharp edge.
For coil anodizing, the coating thickness shall be measured at the beginning, in the middle
and at the end of each strip.
Measurement of thickness shall be dealt with in a lot acceptance test.
9.3 Sealing tests
9.3.1 Mass loss test with predip
This test assesses the ability of the surface of an anodic oxidation coating to resist chemical
attack by an acid.
This test shall be carried out as specified by ISO 3210:2010 method 2 which includes the prior
acid treatment in a nitric acid solution, but with changes to the procedure as specified below.
The test solution shall be an aqueous solution containing 35 ml of phosphoric acid (ρ20 = 1,7
g/ml) per litre.
The immersion time in the phosphoric acid solution shall be 13 min.
The maximum permissible loss of mass shall be 30,0 mg/dm².
The phosphoric acid test solution attacks bare metal to a limited extent. However, for alloys
AA 5005, 6060 and 6063 it is not necessary to take uncoated surfaces into account if the
uncoated area is not greater than 20% of the total area of the specimen. The dissolution of
uncoated specimens of the above alloys does not exceed 10 mg/dm2 over the acid immersion
procedures of method 2.
The test shall not be used if the uncoated area is greater than 20% of the total area of the
specimen.
Test specimens may be taken from hollow profiles if the requirements of ISO 3210:2010 can
be met. “For hollow extrusions, take the test piece from the end of the sections where the total
surface area has an anodic oxidation coating (due to the throwing power of the anodizing
electrolyte).”
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If it is not possible to take test specimens from the production lot, the anodizer may carry out
the mass loss test on special test specimens made of the same alloy as the production lot and
treated simultaneously with it. This shall be mentioned in the register.
The dissolution of the uncoated specimen of the metal may be determined using an uncoated
specimen of the same alloy.
The mass loss test shall be carried out not more than 2 weeks after sealing.
9.3.2 Mass loss test without predip
This test assesses the ability of the surface of an anodic oxidation coating to resist chemical
attack by an acid.
This test shall be carried out as specified by ISO 3210:2010 method 1 but with changes to the
procedure as specified in 9.3.1.
9.3.3 Dye spot test
This test provides an assessment of the absorptive power of the outer surface of anodic
oxidation coatings, which is reduced by sealing.
The absorptive power shall be determined in accordance with ISO 2143. This test shall always
be carried out on the part with the thickest coating.
The test is applicable only to clear and light-coloured anodized aluminium.
The chemical supplier’s instructions to prepare the test solutions shall be followed. If the
colorant solutions described in the standard ISO 2143 are stored properly, they will remain
stable for up to two years. However, their pH values should be checked every 3 months. If the
pH of a solution is outside the range prescribed by the chemical supplier, then it should be
corrected following the chemical supplier’s instructions.
9.3.4 Admittance test
This test measures the electrical admittance of the whole thickness of the anodic oxidation
coating, which is reduced by sealing.
The admittance shall be determined in accordance with ISO 2931.
This test is not applicable to any of the following:
• cold sealed parts;
• alloys containing more than 2% of silicon, 1.5% of manganese or 3% of magnesium.
The acceptance limits for the admittance test that are applied to uncoloured finishes are not
applicable to electrolytically coloured parts in medium bronze, dark bronze and black. Those
are finishes with an L* value less than about 60 on the CIE 1976 L* a* b* scale.
9.4 Appearance
9.4.1 Visible defects
Defects can include marks, scratches, indentations, corrosion, flatness, welding artefacts,
streaks, pick-up and hot spots.
The significant surface(s) of anodized parts shall be assessed by visual examination. Where
the products are going to be used under natural lighting conditions, unless otherwise agreed,
specimens or components shall be compared in diffuse daylight with the sun behind the
viewer. If the products are to be used in artificial light, that lighting shall be used for the
comparison, and a diffuse source of illumination shall be placed above and behind the viewer.
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9.4.2 Surface texture and colour
The comparative assessment of appearance shall be carried out visually or, for production
control purposes, it may be carried out using an instrumental method.
For a comparative visual assessment, specimens or components shall be set in the same
plane and viewed as near to normal as is practicable with the direction of working (eg the
rolling, extrusion or machining direction) always the same.
Where the products are going to be used under natural lighting conditions, unless otherwise
agreed, specimens or components shall be compared in diffuse daylight with the sun behind
the viewer. If the products are to be used in artificial light, this lighting shall be used for the
comparison, and a diffuse source of illumination shall be placed above and behind the viewer.
For surface texture, instrumental measurement shall be performed in accordance with the
requirements of either ISO 6719 or 7668 following the guidance of ISO 7599. The use of
instrumental methods to assess colour is not recommended.
9.4.3 Light reflection properties
The assessment of light reflection properties shall be carried out in compliance with ISO 7599
using instrumental methods specified in ISO 6719, 7668, 7759, 10215 and 10216 as agreed
by the licensee and the customer.
9.5 Corrosion resistance
The corrosion resistance of anodized aluminium shall be determined by using one of the
methods specified in ISO 9227. The duration of the acetic acid salt spray test (AASS) shall
be 1000 h. The duration of the neutral salt spray test (NSS) shall be 336 h.
The test samples shall have dimensions not less than 150 mm x 70 mm x 1 mm.
These methods are not suitable for unsealed anodic oxidation coatings.
The corrosivity of the salt spray cabinet shall be checked following the method for evaluating
cabinet corrosivity specified in ISO 9227. During permanent operation, the time interval
between corrosivity checks shall not be more than three months. The test report shall include
the date of the last corrosivity check.
9.6 Resistance to wear / abrasion
This includes methods that assess the resistance to wear of the surface of an anodic oxidation
coating (surface abrasion resistance) and those that assess the resistance to wear of the
whole thickness of an anodic oxidation coating (bulk wear resistance). Some of the methods
assess resistance to abrasive wear and others the resistance to erosive wear.
9.6.1
Manual test
9.6.1.1 Principle
The test is based on Mohs’s principle that a substance will be scratched only by a material
harder than itself. The surface abrasion resistance of an anodic coating is evaluated by using
a glass-coated abrasive paper to determine whether or not the coating is harder than the
glass-coated abrasive paper. It is a test for anodic film quality.
9.6.1.2 Scope
The test is applicable to anodic oxidation coatings produced by sulfuric acid‐based anodizing.
It is not applicable to anodic oxidation coatings produced by hard anodizing or integral
colouring methods.
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9.6.1.3 Apparatus
Validated glass-coated abrasive paper. It should be used as strips 12 mm wide and 150 to
200 mm long. Note that the paper should be kept in a warm, dry place.
Glass-coated abrasive paper can be validated by testing it using standard specimens. Type
P standard specimens pass the test using valid paper while type F standard specimens fail
the test using valid paper. Qualanod can provide information on sourcing standard specimens.
Resilient support for the paper during the test, 6 mm to 8 mm thick and approximately 30 mm
wide and 40 mm long. The hardness of the support shall be 30 to 70 International Rubber
Hardness Degrees (IRHD). A rubber or soft‐plastic pencil eraser can be suitable.
9.6.1.4 Test specimen
The test specimen normally consists of a production article (or part thereof), which has been
fully processed and is clean and dry. If the test specimen is a production article (or part
thereof), the test shall be performed on a significant surface.
9.6.1.5 Test method
Wrap the glass‐coated paper round the resilient support with the abrasive side outwards and
lying across the narrow part of the block as shown in Figure 2. Hold the paper tightly in place
as shown and pressing the abrasive strip firmly against the anodic oxide surface, make 10
double strokes (one double stroke is one passage backwards and forwards across the test
area) with an amplitude of 25‐30 mm. It is important that the abrasive paper lies flat on the
anodic oxide surface. After 10 double strokes examine the part of the abrasive paper which
has been in contact with the anodic oxidation coating.
Fig 2. Drawings showing how to use the glass‐coated paper.
If the anodic oxidation coating is harder than the abrasive, the paper slips easily across the
surface and the coating is merely burnished. If the abrasive is harder than the coating, a
definite resistance is felt as the abrasive bites into the coating. The coating is degraded and a
significant quantity of dense, chalky white powder is deposited on the abrasive paper (Fig. 3a)
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Fig 3. Photographs of specimens of glass‐coated abrasive paper specimens exhibiting:
a) a dense, chalky white powder deposit; b) a light powder deposit.
A light powder deposit (Fig. 3b), not filling completely all the spaces between the abrasive
particles, can indicate the removal of a very thin, superficial sealing smut. If in doubt, wipe the
tested area clean with a dry cloth, locate a fresh area of abrasive paper round the support and
test again in the original area.
Note. It can be helpful to test a vertical surface so that any loose abraded particles fall away
and do not themselves cause abrasion.
9.6.2 Abrasive wheel
This test assesses the resistance of an anodic oxidation coating to abrasive wear.
This is the referee test to assess the surface abrasion resistance of an anodic oxidation
coating.
The resistance to abrasive wear shall be determined by using the abrasive wheel wear test
method described in ISO 8251.
9.6.3 Abrasive jet
This test assesses the resistance of an anodic oxidation coating to erosive wear.
The resistance to a jet of erosive material shall be determined by using the abrasive jet test
method described in ISO 8251.
9.6.4 Falling sand
This test assesses the resistance of an anodic oxidation coating to erosive wear.
The resistance to erosion by falling sand shall be determined by using the falling sand abrasion
method described in ISO 8251.
9.6.5 Taber abrader
This test assesses the resistance of an anodic oxidation coating to abrasive wear. The method
used shall be that described in ISO 10074.
9.7 Microhardness
The microhardness of an anodic oxidation coating shall be determined by using the Vickers
microhardness method of ISO 4516.
9.8 Resistance to cracking by deformation
The resistance to cracking by deformation of an anodic oxidation coating shall be determined
by using the method specified in ISO 3211.
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Assessing resistance to deformation can be relevant for rolled products that are deformed
after anodizing.
9.9 Fastness to light and ultraviolet radiation
9.9.1 Light fastness
The light fastness of anodized aluminium shall be determined by using the method of ISO
2135.
This is an accelerated test method using artificial light. It is suitable as a production control
test for coloured coatings, the lightfastness of which has been determined by outdoor
exposure testing. It is not suitable for coloured coatings with a lightfastness number of less
than 6.
9.9.2 Fastness to ultraviolet radiation and heat
The fastness of anodized aluminium to ultraviolet radiation and heat shall be determined by
using the method of ISO 6581.
This is a comparative method. It is not suitable for testing coloured coatings that are heat
sensitive.
9.10 Electrical breakdown potential
The electrical breakdown potential of an anodic oxidation coating shall be determined by one
of the methods specified in ISO 2376.
The methods are applicable to sealed coatings used primarily as electrical insulators. Note
that breakdown potential is affected by relative humidity.
9.11 Coating continuity
The continuity of an anodic oxidation coating shall be determined by the method specified in
ISO 2085.
The method is applicable to coatings that have been deformed such as those produced by coil
anodizing. It is also applicable to coatings with a thickness less than 5 µm.
9.12 Surface density
The surface density of an anodic oxidation coating shall be determined by the method
specified in ISO 2106.
The method is not suitable for coatings on aluminium alloys with a copper content greater than
6%. Note that if the thickness or apparent density of the coating is known, then the surface
density can be used to calculate the value of the unknown property.
9.13 Thermal craze resistance
The resistance to heat-induced crazing of an anodic oxidation coating shall be determined as
follows.
• Place a specimen of the material to be tested in an oven that has been preheated to 50
°C and is capable of maintaining a temperature which does not vary more than ±3 °C.
• After 30 minutes, visually check the specimen for crazing. If no crazing is present,
increase the oven temperature by 5 °C.
• After the oven reaches temperature begin timing for 30 minutes and then recheck the
specimen for crazing.
• If no crazing is present, continue to increase the temperature by 5 °C and recheck in 30
minute intervals until crazing is present.
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9.14 Summary of product tests for the different types of anodizing
Table 2 provides an overview of the tests carried out by the sub-licensee and the tests of an
inspection depending on the anodizing type. It includes references to the sub-clauses that
describe the tests and to the appendices and sub-clauses that specify the tests to be carried
out. The symbol X indicates a test carried out by the sub-licensee while the symbol o indicates
a test carried out by the sub-licensee if agreed with the customer. The sub-licensee may
contract the testing to another organization. Note that there are special rules for light fastness
tests that specify circumstances where the sub-licensee does not have to carry out the tests.
In all cases, certain conditions and particular requirements can apply; these are specified in
the appropriate sub-clauses. Thus, it is essential that these are consulted rather than relying
solely on Table 2. Shaded cells in Table 2 indicate the tests of an inspection. Note that
inspections do not include tests for visible defects, and surface texture and colour because
appearance can be readily checked by the customer.
Table 2. Product tests carried out by the sub-licensee and those of an inspection
Product test
Coating thickness
Final dimensional tolerances
Mass loss (with predip)
Mass loss (no predip)
Dye spot
Admittance
Surface defects (no specified
distance)
Surface defects at 5m & 3m
Surface defects at 2m & 0.5m
Texture & colour
Light reflection
Corrosion resistance (AASS)
Corrosion resistance (NSS)
Surface abrasion resistance
Surface abrasion resistance
Wear resistance (abrasive
wheel)
Wear resistance (abrasive jet)
Wear resistance (falling sand)
Wear resistance (Taber
method)
Microhardness
Resistance to cracking by
deformation
Light fastness
Resistance to ultraviolet
radiation
Electrical breakdown potential
Coating continuity
Surface density
Thermal craze resistance
Roughness
Service simulation tests
QUALANOD SPECIFICATIONS
Subclause
Type of anodizing
Architectural
Industrial
Decorative
Hard
both
appearance
and protection
are important
12.7 & 12.11
appearance
is secondary
or of no
importance
13.7 & 13.11
decorative
finish is the
primary
characteristic
14.7 & 14.11
high wear
resistance
9.2
X
X
9.3.1
9.3.2
9.3.3
9.3.4
X
X
o
o
X
9.4.1
9.4.1
9.4.1
9.4.2
9.4.3
9.5
9.5
9.6.1
9.6.2
o
X
X
X
X
X
X
X
X
o
X
X
o
o
o
X
X
9.6.2
o
9.6.3
9.6.4
o
9.6.5
X
o
9.7
o
9.8
o
9.9.1
X
o
o
o
o
9.9.2
9.10
9.11
9.12
9.13
15.7 & 15.11
o
o
o
o
o
o
o
o
o
o
o
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o
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Approval of new processes and products
It is important that new processes and products which are used in the production of anodized
aluminium for external architectural applications are tested and approved by Qualanod. This
is because the effects of weathering can be long term and are very variable, and cannot be
effectively simulated by laboratory tests. The testing and approval of new processes and
products for use in the production of anodized aluminium for other applications is not
necessary if effective laboratory tests or simulations of service conditions can be applied.
A new process or product requires testing and approval if it could affect the outdoor service
performance of the anodized aluminium. This includes new processes and products for
anodizing and sealing but can include other new processes and products applied after the
anodizing step in an anodizing line.
Licensees that are licensed for products of clause 12, architectural anodizing, shall use only
processes and products for anodizing and subsequent processes in an anodizing line that are
well-established for use in anodizing lines or have current approval from Qualanod.
Established processes and products include oxalic acid additions to anodizing baths, dyeing
(including fixing the dye using a solution containing a nickel salt), colouring by the
electrodeposition of a metal or metal oxide, hydrothermal sealing (including pre-sealing in a
triethanolamine solution) and two-step cold sealing using a solution containing nickel fluoride.
Before a licensee that is licensed for products of clause 12, architectural anodizing, may use
a new process or product, it shall enquire of Qualanod whether the use of the process or
product is well-established or has current approval. If neither is the case, then an application
may be made to have it assessed for approval. The procedure is specified in a separate
document that is available from the Qualanod secretariat.
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Guidance on products and processes
11.1 General
This clause provides guidance and recommendations. None of its content is mandatory for
compliance with these Specifications.
11.2 The aluminium to be anodized
11.2.1 Architectural anodizing
The most commonly used alloys for anodizing for external architectural applications are AA
1000, 5000 and sometimes 3000 series for rolled products, and 6000 series for extruded
products. Table 3 gives guidance on alloys suitable for anodizing and includes other alloys
normally regarded as having a good anodizing response for decorative and protective
applications. These materials do not have the same appearance after anodizing even
sometimes for the same alloy. This is because the appearance after pretreatment and
anodizing is strongly influenced by the alloy microstructure. Microstructure depends on both
the metallurgical processes used and the alloy composition. Furthermore, specifications for
alloy composition given in national and international standards are very broad; producers of
alloys suitable for anodizing have their own proprietary specifications which are much
narrower. As even slight differences in metallurgical microstructure can lead to significant
differences in appearance, it is recommended that if possible, material from different lots
should not be mixed for single projects.
For aluminium structures covered by Eurocode (EN 1999‐1‐1) only alloys which are listed in
the Eurocode may be used. These alloys are indicated by an asterix in Table 3.
The customer should specify the alloy and attest that the semi-finished product conforms to
the relevant standard for technical conditions of inspection and delivery, eg ISO 6362-1, EN
485-1, EN 586-1, EN 754-1, EN 755-1, EN 12020-1. Such standards specify composition in
accordance with EN 573-3 and freedom from surface defects. Also, they recommend that
semi-finished products intended to be anodized should be subject to an anodizability test by
the producer before delivery, and that the frequency and the method of the test should be
agreed between the producer and its customer. A suitable test is the treatment of a specimen
of the product through an anodizing line to produce the finish agreed by the licensee and its
customer; the specimen is subsequently assessed by visual examination.
Alloys other than those given in Table 3 can be used if required by the customer who should
specify in writing the anodizing thickness class.
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Table 3. Alloys suitable for architectural anodizing
Series (AA)
Alloying
constituents
Metal
properties
1xxx
None
5xxx
Magnesium
6xxx
Magnesium and Strong
silicon
Ductile
Alloys (AA)
Anodized
metal
properties
Soft
1050A
Clear
Conductive
1080A
Bright
Finishing advice: care should be taken when racking this soft material; good for bright
products; susceptible to etch staining.
Strong
Ductile
5005*
Clear
5005A*
Good protection
5050
5251
5657
5754*
Finishing advice: for 5005 and 5005A, keep Si < 0,1% and Mg between 0,7% and 0.9%;
inspect for oxide streaks; 5005 and 5005A are used extensively in architectural applications.
6060*
Clear
6063*
Good protection
6063A*
6463
Finishing advice: for a matt finish, keep Fe > 0,22%; for a bright finish, keep Fe < 0,15%;
6060 and 6063 can be the best match for 5005 and 5005A; 6463 can be the best for
chemical brightening; variations in Fe content and other elements can influence the final
appearance after anodizing.
11.2.2 Industrial and hard anodizing
Table 4 gives guidance on the selection of alloys for industrial applications. Although hard
anodizing can be applied to many alloys, those with more than 5% copper and/or 8% silicon
and die casting alloys require special anodizing procedures. Alloys with low contents of
alloying elements give the best microhardness and wear resistance and lowest surface
roughness.
Table 4. Guidance on alloys for industrial and hard anodizing
Alloy (AA)
Corrosion protection
Wear resistance
1080, 1050A
1200
2011, 2014A, 2017A, 2024, 2030, 2031
3003, 3103, 3105
4043A
5005, 5050, 5052
5056A
5083
5154A, 5251, 5454, 5754
6005A, 6061, 6463
6060, 6063
6082, 7020, 7022, 7075
Excellent
Very good
Mediocre
Good
Good
Excellent
Good
Good
Very good
Very good
Excellent
Good
Excellent
Excellent
Good
Good
Good
Excellent
Excellent
Good
Excellent
Very good
Excellent
Good
Before anodizing, sharp edges should be machined to a radius of at least 10 times the
intended coating thickness to avoid burning. Generally articles should not be subjected to any
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heat-treatment, machining, welding, forming and perforating operations after anodizing,
although grinding is sometimes used to achieve dimensional tolerances.
11.2.3 Decorative anodizing
To produce particularly decorative effects or a particularly uniform appearance, alloys of
anodizing quality should be used. These are produced by special manufacturing techniques.
Thus, there is no national or international standard for anodizing quality because the term
refers to particular production schedules devised by the manufacturers.
Higher purity aluminium or special alloys should be used to produce a high-lustre surface.
The general effects of alloying elements are as follows.
• Iron. Reduces specular brightness. High iron to silicon ratios lead to dark streaks.
• Silicon. Cloudiness when out of solid solution. Over 5 % silicon leads to dark grey or
black coatings.
• Magnesium. Up to 3 % magnesium leads to colourless coatings.
• Copper. Increases specular brightness. Over 2 % copper leads to discoloration.
• Manganese. Up to 1 % manganese can lead to clear, silver, grey, brown or mottled
coatings depending on the alloy microstructure.
• Zinc. Up to 5 % zinc can lead to colourless, brown or marbled coatings depending on
the alloy microstructure.
• Chromium. 3 % chromium leads to yellow coatings.
Special alloys for integral colour anodizing and "self-colouring" alloys for the sulfuric or sulfuricoxalic process can be used to produce certain colours.
11.3 Anodic oxidation coating thickness
11.3.1 Architectural anodizing
For anodized aluminium, the degree of protection against pitting corrosion of the aluminium
increases with an increase in coating thickness. Thus, product life time is very dependent on
the coating thickness. However, there is greater energy expenditure associated with thicker
coatings. Thus, over-anodizing is not recommended. For external architectural applications,
the choice of thickness class depends on the aggressive nature of the environment and can
be determined by national standards.
The use of some dyestuffs necessitates the specification of class 20 or higher to obtain
adequate dye absorption and light fastness.
11.3.2 Industrial and hard anodizing
Coatings are generally 15 µm to 150 µm thick. Products such as splines and threads can
have coatings up to 25 µm thick. Insulator requirements are often satisfied by coatings of 15
µm to 80 µm thickness. Coatings of 150 µm thickness are used for repair purposes.
11.4 Appearance
11.4.1 Defects
Defects can include marks, scratches, indentations, corrosion, flatness, welding artefacts,
streaks, pick-up and hot spots.
11.4.2 Surface texture
ISO 7599 includes a surface preparation designation system. The appearance of the final
product depends on the surface treatment immediately prior to anodizing. The requirements
for uniformity of appearance relate to the permissible variations in the alloy including variations
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caused by the manufacturing process, and to variations in the treatment by the anodizing
plant.
The extent of admissible variations in the final appearance and uniformity should be agreed
by means of reference specimens that have the required coating thickness and are acceptable
to both parties. Also, the method of assessment should be agreed by both parties. It should
be noted that it is not possible to specify “upper” and “lower” limits on appearance because a
number of different factors contribute. For example, although specular gloss varies on a scale
up to 100, it is possible for specimens with similar gloss values to look quite different under
visual assessment.
When using instrumental methods to quantify surface texture, it is important to be attentive to
any dependence of measuring on specimen orientation (working direction), and to set
operating procedures accordingly. For example, specular gloss should be measured by
placing the specimen in contact with the instrument so that the plane of incidence and
reflection is parallel to the working direction of the metal.
11.5 Equipment of anodizing plants
11.5.1 Tanks
The material and/or lining of the tanks should be chosen in order to avoid any risk of
contamination of the solutions.
The volume of the anodizing baths should be in proportion to the amperage to ensure that the
required current density can be achieved and the specified temperature maintained.
11.5.2 Cooling of the anodizing electrolyte
The cooling capacity of the system used should be capable of absorbing all the heat generated
during the electrolytic process at maximum utilization of the electrical capacity installed, and
at the rate it is generated. The heat generated in calories per hour by normal anodizing at the
working temperature is approximately
0,86 x I x (V + 3) = K
where I is the maximum current in amperes, V is the maximum voltage in volts and K is the
cooling capacity in kcal/h. Ambient conditions should be taken into consideration when
calculating the total cooling capacity.
11.5.3 Agitation of the anodizing electrolyte
Electrolyte movement relative to the workpieces should be sufficient to remove excess heat
generated at the surface of the aluminium during the anodizing process.
It is a vital factor in maintaining the electrolyte temperature around the work pieces because
insufficient heat transfer can lead to poor anodic film quality. Adequate agitation can be
achieved by hydraulic turbulence or air agitation. For batch processing, agitation of the
electrolyte by conventional pump-recirculation is generally not sufficient to maintain proper
temperature control in the bath. However, hydraulic turbulence produced by a pumped system
with eductor nozzles placed at the bottom of the tank is effective for batch processing.
Although the energy required is greater than that needed for low pressure air agitation, the
difference can be comparable to the energy loss through evaporation of water from air agitated
tanks. Hydraulic turbulence provides greater agitation than air systems, which can improve
the thickness uniformity over the loads and reduce the possibility of burning. Furthermore,
there is less acid mist evolved from the surface of the solution.
If air agitation is chosen, a minimum of 5 m3/h per square metre of bath surface should be
used (measured with a rotameter); the recommended value is 12 m3/h per square metre of
bath surface. Note that air bubbles increase the resistivity of the solution by up to 35%, which
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increases the electrical energy consumption for anodizing. The air flow should ensure that the
electrolyte is evenly agitated over the whole surface of the bath. This is best achieved using a
large volume of low pressure air from a blower rather than a compressor. The use of
compressed air gives high evaporative heat losses especially when used in conjunction with
air extraction. Note that it is not “best available technique” (BAT) to use high pressure air
agitation because of the high energy consumption. However, if a compressor is used, the
dimensions of the pipes and agitation holes should be adjusted to give even agitation.
11.5.4 Heating
The heating capacity of the individual baths should be related to the temperatures to be
maintained during the various stages of treatment. In particular, it should be possible to
maintain the temperature of the hydrothermal sealing baths at a minimum of 96 °C during the
sealing process.
11.5.5 Current supply
The electric equipment and installations (rectifiers and busbars) should be capable of
generating the required current density for a load at the maximum installed rectifier capacity.
It should be possible to regulate the DC supply in steps of no more than 0,5 V.
The rate at which the voltage is applied is not critical. However, a slow reduction in voltage at
the end of the cycle can cause the anodic oxidation coating to be attacked.
The scales on voltmeters and ammeters should be such that each division represents a
maximum of 2% (volts) and 5% (amperes) of the total scale deflection.
The measuring instruments should be in the precision class 1,5%, and should be checked
twice a year.
When using current supplies with complicated frequency waveforms, care should be taken to
ensure that the current-measuring instrument measures the true main current. It is very
important to work with the correct current density and this means that the actual current
supplied to the tank should be measured.
The voltage drop across the busbar to flightbar contact should not be more than 0,3 V; the
temperature should not rise to more than 30 °C above the ambient temperature.
11.5.6 Jigs
Aluminium supporting jigs submerged in the electrolyte should have a cross section
representing more than 0,2 mm²/A. Larger sections are required for titanium which has higher
resistance.
The number and size of the contacts should be sufficient to conduct the current evenly to all
parts in the load and over the whole surface of each part. Pressure on the contacts should be
sufficiently high to prevent oxidation of the points of contact and any movement of the parts
during electrolysis.
The workpieces should be arranged on the jigs in such a way as to minimize anodic film
thickness variation. Workpieces jigged very densely or multiple rows of workpieces without
intermediate cathodes can lead to increased film thickness variation. Systems with central
cathodes between the rows of workpieces are recommended.
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11.6 Processes of anodizing plants
11.6.1 Rinsing
At least one separate rinse should be performed after each stage of treatment (surface
preparation, anodizing, colouring).
Some stages of treatment require several rinses. This is particularly true of anodizing. As the
first rinse is usually very acidic a second rinse is necessary before colouring or sealing.
Anodized workpieces should never be left for more than 1 to 2 minutes in the acid rinse.
Workpieces left in an acid rinse for some time show signs of film attack.
11.6.2 Etching
In order to achieve a high level of consistency and uniformity, it is important to properly control
the etching process. The anodizing plant should follow closely the instructions from the
supplier of the etch chemicals and, where available, the supplier of the semi-fabricated
product. In the absence of full instructions, the anodizing plant should take particular measures
indicated below.
In order to achieve a consistent product, it is necessary to control within tight tolerances the
concentrations of free sodium hydroxide, aluminium and any sequestrant, and the solution
temperature. Solution composition can be effectively controlled by using a crystallizer to
continuously regenerate the solution or by using a “long-life” etch where the masses of
materials entering and leaving the etch solution are balanced.
Whereas during etching, aluminium loses mass at a constant rate, the gloss falls at a
decreasing rate. After a certain time depending on the etching conditions, an approximately
constant gloss level is achieved. Anodizing plants should identify this regime for their particular
etch conditions and set the processing time accordingly. This makes the process very much
more controllable and reduces product inconsistency that can arise from poor reproducibility
of etching time, excessive drainage time after the load has been withdrawn from the etch tank
and excessive rinsing at relatively high pH values.
11.6.3 Architectural and decorative anodizing
11.6.3.1 Sulfuric acid electrolytes
The concentration of free H2SO4 should be not more than 200 g/l, variable within 10 g/l of the
selected value.
The aluminium content should be not more than 20 g/l but preferably within 5 to 15 g/l.
The chloride content should be not more than 100 mg/l.
The acid concentration is only critical at high anodizing temperatures. High acid
concentrations lower the anodizing voltage required (about 0,04 V per g/l of H2SO4), but also
lead to greater drag-out and higher acid consumption. Low aluminium contents increase the
sensitivity of the film to high bath temperatures. The higher the aluminium content, the higher
the anodizing voltage required (about 0,2 V per g/l of aluminium). Chloride in the anodizing
electrolyte can cause pitting during anodizing and has been found to adversely affect
resistance to weathering.
11.6.3.2 Sulfuric acid - oxalic acid electrolytes
The concentration of free H2SO4 should be not more than 200 g/l, variable within 10 g/l of the
selected value.
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The concentration of oxalic acid should be at least 7 g/l. 5 g/l of oxalic acid is too low to have
an effect and increasing the level improves the film quality. Oxalic acid concentrations of over
15 g/l have no advantage and increase the production costs.
The aluminium content should be not more than 20 g/l but preferably within 5 to 15 g/l.
11.6.3.3 Temperature of sulfuric acid bath
This should be controllable within 1,5 °C of the selected temperature regardless of the size of
the load. The maximum acceptable temperature difference in the bath in the vicinity of the
workpieces should be 2 °C and within the maximum range prescribed.
Thickness classes and actual bath temperature:
• AA 5 and AA 10 not above 21 °C
• AA 15, AA 20 and AA 25 not above 20 °C
These temperatures represent the maximum temperature at any time and anywhere in the
electrolytic bath during the process. The anodizing electrolyte temperature is the single most
critical factor affecting anodic film quality and excessive temperatures caused by poor control,
poor agitation or poor jigging are responsible for most anodizing quality problems.
11.6.3.4 Temperature of sulfuric acid-oxalic acid bath
This should be controllable within 1,5 °C of the selected temperature regardless of the size of
the load. The maximum acceptable temperature difference in the bath in the vicinity of the
workpieces should be 2 °C and within the maximum range prescribed.
For all thickness classes the bath temperature should not be above 24 °C.
This temperature represents the maximum temperature at any time and anywhere in the
electrolytic bath during the process.
11.6.3.5 Current density
For sulfuric acid-based anodizing, the average current density should be:
• 1,2 – 2,0 A/dm² for AA 5, AA 10
• 1,4 – 2,0 A/dm² for AA 15
• 1,5 – 2,0 A/dm² for AA 20
• 1,5 – 3,0 A/dm² for AA 25
A risk factor for quality is the use of low current densities to produce thick coatings (AA 20 and
AA 25). High current densities require good contacts and good agitation but are less likely to
give quality problems.
AA 25 needs special care. When carrying out electrocolouring to produce very dark bronze
or black, the anodizing time should be less than 50 minutes unless special measures are
undertaken to control the bath temperature at the surface of the work. The maximum coating
thickness should be less than 35 µm.
11.6.3.6 Anodizing electrodes (cathodes)
The cathode to anode (working surface) ratio should be in the region of 1:1,5 to 1:2,5.
Aluminium cathodes are recommended. For cathodes on the side of the tank, only one side
should be considered; for central cathodes, both sides should be considered. Where there is
a high cathode to anode ratio the use of lead lined tanks without shielding can lead to film
thickness variation problems. Aluminium electrodes require the lowest operating voltages.
The distance between the cathode and the anode should not be less than 150 mm.
11.6.3.7 Transfer of the workpieces after anodizing
When the anodizing cycle has been completed, the workpieces should be transferred from the
anodizing electrolyte to the rinse as quickly as possible. They should never be left in an
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anodizing bath without current. This is another factor that can cause film attack and
deterioration in film quality particularly at the film surface.
11.6.4 Sealing for architectural anodizing
11.6.4.1 Hydrothermal sealing
Phosphates, fluorides and silicates inhibit the sealing process.
Where an additive is used in the sealing baths (for instance to prevent smutting), special care
should be exercised and greater attention paid to the referee test and the mass loss results
and, where appropriate, the dye spot test.
The sealing time necessary to get a good sealing should be at least 2 minutes per micrometre
coating thickness unless there is a preseal.
For steam sealing the minimum temperature should be the saturated steam temperature.
11.6.4.2 Cold sealing process based on nickel salts and fluorinated salts
This section gives prescriptions for the implementation of "cold sealing" processes based on
nickel salts and fluorinated salts (notes 1, 2 and 3). It incorporates the knowledge about these
processes gained in the past years, and defines the most important parameters. The process
is divided into 2 steps: in the first one the anodic coating is sealed, in the second one the
anodic coating is hydrated.
Anodizing conditions
As for other sealing processes it is essential to produce a good quality anodic oxide film
according to the conditions stipulated in this clause.
Note 1. Cold sealing processes are based on chemicals which diffuse into the pores of the
anodic oxide film and initiate a chemical reaction. It depends not only on the temperature but
also on the chemicals used and other process factors. This specification relates only to cold
sealing processes based on nickel fluoride.
Note 2. The product available on the market can be a “mixture” of nickel salts and fluorides
or fluorinated salts, where nickel fluoride can be only a minor part of the total amount.
Note 3. Since the consumption of fluoride is slightly higher than the stoichiometric amount of
nickel, some products on the market contain a slight excess of fluorides.
First step of the sealing process
1) Concentration of the product: nickel ion content at 1.5 ± 0,3 g/l; free fluoride ions at a level
within the range 0,3 to 1,0 g/l
2) Bath temperature: 25 to 30 °C
3) pH: 5,8 – 7,0 (preferably 6,5 ± 0,2)
4) Sealing time: 1,0 ± 0,2 min/μm of the anodic coating
5) Phosphate ions in the solution less than 5 mg/l
Rinsing after the first step of the cold sealing process is essential and it is the responsibility of
the supplier to prescribe the conditions.
Note 4. An excess of fluorides, especially in presence of a low pH produces a rapid
degradation of the solution due to a chemical attack to the oxide surface. This attack is evident
especially on polished or brightened parts.
Note 5. An excess of ions different from nickel and fluoride can induce a reduction in the
activity of the solution; in this case filtration can help to overcome the problem.
Supplementary requirements
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The supplier should give the anodizing plant precise details of the percentage of active
chemical components and, if a powder, the percentage of insoluble matter in the products.
The quality of the water for the preparation of the bath should be checked before use; it is
advisable to use deionized water to make up the bath.
The operating parameters for cold sealing are critically important and, as indicated below,
should be closely controlled to achieve a satisfactory result. It is also important to remember
that the parameters are interdependent; for example, a high fluoride ion concentration requires
a lower operating temperature and/or a shorter sealing time and a higher pH.
Bath concentration
The most important bath constituents are nickel and fluoride. An excess of free fluoride ions
can damage the anodic coating.
In some cases, 5 - 10% of the nickel is substituted by cobalt to minimize the greenish shade.
After analyses, the bath should be replenished with extreme care avoiding its use until the
substances added have been fully solubilized.
Sometimes, nickel fluoride can contain insoluble matter. It is advisable to make additions in a
mixing chamber outside the bath. Moreover, fluoride is consumed at a higher rate than nickel,
and additions of ammonium or potassium fluoride will be required to maintain the correct
balance.
Analytical methods for checking the baths should be provided by the supplier. Generally an
EDTA method is used for nickel and a potentiometric method with an ion-sensitive electrode
for free fluoride.
Note 6. It is advisable to avoid the use of hydrofluoric acid or too acidic fluorinated salts able
to unbalance the pH of the solution. Strong variations of pH are never positive for the final
quality.
Bath temperature
The bath temperature should be maintained with a sensitive thermostatic device.
This parameter has a great influence on the kinetics of the process. Too high a temperature,
particularly when the free fluoride concentration is at a high level, causes damage to the
anodic oxide film and results in a powdery surface.
Bath pH
The pH of the solution should be preferably 6,5 ± 0,2. Generally, the higher the pH the better,
but it is not possible to go above 7,0 without causing a slight precipitation of nickel hydroxide.
The pH affects the amount of nickel precipitated in the pores, and below 5,8 insufficient nickel
is deposited, and a chemical attack on the anodic coating can be generated by fluoride.
Note 7. The pH should be measured with utmost care as fluoride in the solution can attack
the pH electrodes or damage the glass membrane. This makes it very important to check the
pH electrodes at regular intervals.
Rinsing
Rinsing should be sufficiently thorough to minimize the carry-over of fluoride ions into the
second step.
Second step of the sealing process
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To complete the cold sealing process, the treated parts should be exposed to high humidity
for some time, which can be accelerated by dipping the cold sealed parts in a water bath at
an elevated temperature. The bath should be operated at a temperature of at least 60°C
(preferably 70°C).
This treatment makes the work easier to handle and check, and is an essential part of the
treatment.
Thorough rinsing between cold sealing and the elevated-temperature water treatment is
absolutely essential as the fluoride ions can inhibit the hydration process.
Cold sealed films are more prone to crazing than conventionally sealed films, especially when
exposed in warm, dry environments. This effect is greatly reduced by the hydration treatment
at elevated temperature after cold sealing.
Note 8. Although not essential, it can be advantageous to use hard city-water for rinsing before
the second step because it causes the precipitation of fluoride.
Quality control
If the cold sealing process including both the first and second step is applied as described
above, the sealed work can be tested in the same way as conventionally sealed work.
The most suitable tests are the dye spot test according to ISO 2143 and the mass loss test
according to ISO 3210.
11.7 Cleaning and maintenance
11.7.1 General
A simple maintenance programme based on a realistic appraisal of local conditions ensures
a maximum useful life for anodized structural components at reasonable cost.
The following documents provide further information on this.
• “Cleaning of aluminium in the building industry”, GDA (Gesamtverband der
Aluminiumindustrie e.V.), Düsseldorf, 2006.
• BS 3987, “Specification for anodic oxidation coatings on wrought aluminium for
external architectural applications”, BSI (British Standards Institute), London, 1991.
• “Konservierung und Versiegelung eloxierter oder organisch beschichteter
Metalloberflächen im Fassadenbereich”, Merkblatt 06, GRM (Gütegemeinschaft
Reinigung von Fassaden e.V.), Schwäbisch Gmünd, 2013.
Brief recommendations are given below.
11.7.2 Interior applications
Interior parts can normally be kept clean by wiping them periodically with a soft cloth. If they
have not been cleaned for some time, a neutral cleaning fluid and soft cloth can be used,
followed by rinsing in clear cold water. They can then be polished with a soft, dry cloth to make
them look like new.
11.7.3 Exterior applications
In practice, the frequency with which structural components exposed to the atmosphere should
be cleaned depends on the kind of parts and the aggressiveness of the environment.
For external architectural applications where the decorative appearance and protective
function are particularly important e.g. porches, entrances, shop fronts, etc., weekly cleaning
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is recommended. In this case, i.e. with regular cleaning, it is possible to use clean water and
chamois leather and then wipe the parts down with a soft dry cloth.
Window frames, windowsills and facades should be cleaned regularly, the frequency
depending on the aggressiveness of the environment and the construction of the facades.
This is best done with a neutral, synthetic cleaning fluid and a cloth, sponge, chamois leather
or soft brush. Then rinse with clear water and rub slightly to dry.
Stubborn dirt can be removed with slightly abrasive cleaning agents or bonded fibres covered
with fine neutral polishing powder.
If a preserving agent is applied to the structural components after cleaning, care should be
taken that only an extremely thin water repellent film remains. This should not yellow, not
attract dust and dirt nor have iridescent effects. Waxes, Vaseline, lanolin and similar
substances are not suitable.
Multi-purpose cleaners should meet the same requirements.
Soda solutions, alkalis and acids should always be avoided. Abrasive materials, metallic
cloths, wire brushes, etc. should never be used.
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Appendix – Architectural anodizing
12.1
Introduction
Clauses 2 to 9 contain general provisions that apply irrespective of the type of anodizing. The
following are particularly significant.
• Clause 6. Granting and renewing licences.
• Clause 7. Regulations for the use of the Qualanod label.
• Clause 8. Inspections.
• Clause 9. Test methods for products.
12.2
Scope
This clause specifies requirements for anodizing and products where both appearance and
protection are important.
ISO 7583 defines architectural anodizing as “anodizing to produce an architectural finish to be
used in permanent, exterior and static situations where both appearance and long life are
important.”
The specifications of this clause may be applied to anodizing and products that are used in
other outdoor applications where both appearance and long life are important. Such
applications can include automotive ones.
12.3 Quality label
The use of the quality label shall comply with the requirements of clause 7.
12.4 Agreements with customers
12.4.1 Information to be supplied by the customer
The following information shall be supplied by the customer to the licensee, if necessary in
consultation with the aluminium supplier or the licensee or both.
• The intended service use of the article to be anodized.
• The specification of the aluminium to be anodized (alloy and temper).
• The extent of the significant surface(s) of the article to be anodized.
• The anodic oxidation coating thickness required.
• Any preferred positions and dimensions of the contact (jigging) marks.
• The surface preparation to be used on the aluminium before anodizing and the limits
of variation of the final surface finish.
• The colour of the anodized article and the maximum limits of colour variation.
• The sealing method to be used.
12.4.2 The aluminium to be anodized
Recommendations on the selection of alloys are given in clause 11
12.4.3 Significant surfaces
Significant surfaces are indicated preferably by drawings or by suitably marked samples. In
some cases, there can be different requirements for the finish on different parts of the
significant surface(s).
12.4.4 Thickness class
Anodic oxidation coatings are graded by thickness class which is determined by the minimum
allowed values of the average thickness and the local thickness. The thickness classes are
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designated by the letters “AA”. The definitions of typical thickness classes are given in Table
12-1. Some guidance on the choice of thickness class is given in clause 11.
Table 12-1. Typical thickness classes
Thickness class
Minimum average thickness
(μm)
Minimum local thickness
(μm)
AA10
10
8
AA15
15
12
AA20
20
16
AA25
25
20
12.4.5 Surface preparation
The surface preparation is indicated preferably by means of reference specimens that are
acceptable to both parties.
12.4.6 Colour
The permissible colour variation is indicated preferably by means of reference specimens that
are acceptable to both parties. The specimens can represent agreed darkest and lightest
limits.
12.5 Complaints
Any complaints by customers to anodizers should be made in writing. The anodizer shall
maintain a register of complaints which includes actions taken
12.6 Laboratory and testing apparatus
12.6.1 Laboratory
The anodizing plant shall have laboratory facilities.
12.6.2 Apparatus
12.6.2.1 General
Each apparatus shall conform to the requirements of the appropriate standard for the test
concerned. Each apparatus shall be functional and have a data sheet showing the apparatus
identification number and calibration checks.
12.6.2.2 Apparatus for product testing
Each anodizing plant shall have at least two instruments for measuring thickness using the
eddy current method or one instrument for the eddy current method and one split-beam optical
microscope (9.2).
The anodizing plant shall have the following equipment to carry out the mass loss test (9.3.1):
• analytical balance (precision 0,1 mg)
• drying oven
• desiccator
• heating device
• means of agitating the solution
• chemical products
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If the anodizing plant uses the dye spot test, it shall have solutions available to carry out the
test (9.3.3).
If the anodizing plant uses the admittance test, it shall have at least one instrument for
measuring admittance and a reference unit for checking the reading accuracy of the device
(9.3.4).
If the anodizing plant uses the surface abrasion test, it shall have validated glass-coated paper
(9.6.1).
The anodizing plant shall have access to apparatus to carry out any other product tests
described in 12.7 that are required by the customer.
12.6.2.3 Apparatus for testing baths
The anodizing plant shall have a pH meter and two buffer solutions.
12.7 Product tests to be applied by the licensee
Some subclauses in this section are omitted on purpose.
12.7.1 Required tests
The licensee shall apply the following product quality tests depending on the products it
produces. See below for details.
• Thickness
• Mass loss test
• Either the dye spot test or the admittance test or both
• Assessment for visible defects, surface texture and, if appropriate, colour
• Surface abrasion resistance
In addition, colour-anodized aluminium shall have adequate light fastness; conformity details
are given below.
If it is not possible to take and test specimens from the production lot because of the shape,
size or form of the product, the licensee may carry out tests on specimens made of the same
alloy as the production lot and treated simultaneously with it. This shall be recorded in the
production control system.
The licensee shall have copies of the standards specifying the tests that it applies. The
standards are identified in clause 4.
12.7.2 Thickness
Average and local coating thicknesses shall be measured on products using a method
specified in 9.2. These shall not be lower than the minimum values for the specified thickness
class.
12.7.3 Sealing quality
12.7.3.1 Mass loss test
Anodized products shall be assessed using the method of 9.3.1. The mass loss shall not
exceed 30 mg/dm2.
This shall be the referee test for sealing quality.
The mass loss test shall be carried out at least:
• once a day for each sealing bath if colour-anodized products represent 100% of the
total output in the week;
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•
•
•
once every two days for each sealing bath if colour-anodized products represent more
than 50% and less than 100% of the total output in the week;
once a week for each sealing bath if colour anodized products represent less than 50%
of the total output in the week;
once a day for each coil-anodizing line that is in use.
12.7.3.2 Dye spot test
Anodized products shall be assessed using the method of 9.3.3. The rating shall not exceed
2. If the rating is 2, either a mass loss test shall be carried out or the sealing shall be repeated.
This is a production control test.
The dye spot test shall be carried out at least once for each sealing bath in every work shift.
For coil-anodizing lines, the dye spot test shall be carried out at least once on every coil.
12.7.3.3 Admittance test
Anodized products shall be assessed using the method of 9.3.4. The acceptance limit for the
corrected admittance shall be 20 µS. If the corrected admittance value exceeds 20 μS, either
a mass loss test shall be carried out or the sealing shall be repeated. The acceptance limit
for the admittance is not applicable to electrolytically coloured parts in medium bronze, dark
bronze and black. Those are finishes with an L* value less than about 60 on the CIE 1976 L*
a* b* scale.
This is a production control test.
The admittance test shall be carried out at least once for each sealing bath in every work shift.
It is not necessary to carry out admittance tests on coil-anodized products.
12.7.4 Visible defects
Parts shall be examined visually in compliance with 9.4.1. The anodized parts shall be viewed
from a distance agreed by the interested parties. In the absence of such an agreement, the
following viewing distances shall apply.
• 3 m for outdoor applications where the observer can approach within 5 m of the
anodized article
• 5 m for other outdoor applications
The metal received by the licensee shall be of sufficient quality to be free of visible defects,
depending on the customer’s requirements, on significant surfaces after processing through
the anodizing line. If there is doubt or dispute whether processing through the anodizing line
would sufficiently reduce the visibility of defects or rolling or die lines, the ability to remove or
mask them shall be assessed by treating a specimen of the metal through the anodizing line
to produce the agreed finish and then by visual evaluation as described above.
12.7.5 Surface texture and colour
The surface texture and colour of anodized components and reference specimens shall be
assessed in compliance with 9.4.2. They shall be viewed from a distance agreed by the
interested parties. In the absence of such an agreement, the following viewing distances shall
apply.
• Those described in 12.7.4 for the comparison of anodized components
• 1 m for the comparison of anodized components with reference specimens agreed by
the interested parties
The surface texture and colour of anodized components shall be within the permissible limits
agreed by the licensee and the customer.
Agreed reference specimens shall be stored in a dry place in the dark.
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12.7.8 Surface abrasion resistance
Anodic oxidation coatings of class AA20 or of a thicker class shall be assessed for surface
abrasion resistance using method of 9.6.1 or 9.6.2. After applying the method of 9.6.1, they
shall not exhibit a dense deposit of chalky white powder. After applying the method of 9.6.2,
they shall have a wear index less than 1.4.
In cases of doubt or dispute, the method of 9.6.2 shall be the referee test. Note that this is a
comparative test and requires the use of a standard specimen.
The method of 9.6.1 is a production control test.
An abrasion resistance test shall be carried out at least once per shift on the finished products
from each anodizing tank.
It is not necessary to carry out abrasion tests on coil-anodized products. However, if required
by the customer, an abrasion test shall be carried out at least once on every anodized coil.
12.7.11 Resistance to cracking by deformation
If required by the customer, anodized rolled-products shall be assessed for resistance to
cracking by deformation using the method of 9.8. The test frequency and the acceptance
criterion shall be agreed by the licensee and the customer.
Assessing resistance to deformation can be relevant for rolled products that are deformed
after anodizing.
12.7.12 Light fastness
Colour-anodized aluminium shall be coloured using a technique that has been demonstrated
to produce a product with a light fastness number of at least 8 as defined by the method of
9.9.1.
Note. It has been demonstrated that electrolytically-coloured anodized aluminium conforms
to the specification for light fastness.
12.7.14 Coating continuity
If required by the customer, coil-anodized products shall be assessed for coating continuity
using the method of 9.11. After the test, visual examination shall reveal no black and/or dark
reddish spots on the surface of the specimen.
The coating continuity test shall be carried out once a day for each coil-anodizing line that is
in use.
12.7.18 Service simulation tests
As the service lifetime of products of architectural anodizing is so long, outdoor exposure tests
are not routinely performed.
12.8 Requirements concerning processes
12.8.1 Anodizing
Anodizing shall be carried out using solutions based on sulfuric acid. With the exception of
oxalic acid, no additives shall be used in anodizing solutions unless approved by Qualanod.
12.8.2 Colouring
Instructions from suppliers of dyes shall be followed.
The instructions from suppliers of electrolytic colouring processes shall be followed. For
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external applications, the quality label shall not be used for black finishes produced using
electrolytic colouring with solutions based on copper salts.
12.8.3 Sealing process
Any sealing process applying a principle other than hydrothermal sealing or two-step cold
sealing using a solution containing nickel fluoride shall not be used unless it has been
approved by Qualanod.
12.8.4 Hot water sealing
For hot water sealing, the temperature shall not be below 96 °C 10 minutes after immersion
of the load.
Any additives, eg anti-smut additives, shall be use in accordance with the instructions of the
supplier.
12.8.5 Cold sealing
12.8.5.1 General
The provisions of this section shall be adopted for two-step cold sealing using solutions
containing nickel fluoride.
12.8.5.2 First step of cold sealing
The nickel ion content of the solution shall be maintained at 1,5 ± 0,3 g/l. 5 - 10% of the nickel
may be substituted by cobalt.
The free fluoride ion content of the solution shall be maintained at the level specified by the
supplier of the cold sealing product.
The solution shall be maintained at a temperature between 25 °C and 30 °C.
The pH of the solution shall be maintained between 5,8 and 7,0.
The immersion time shall be 1,0 ± 0,2 min/μm of anodic oxidation coating thickness.
12.8.5.3 Second step of cold sealing
The solution shall comprise either tap water containing 4,0 ± 1,0 g/l nickel sulfate or nickel
acetate, or deionized water containing an antismut additive.
The solution shall be maintained at a temperature of at least 60 °C (preferably 70°C).
The immersion time shall be 1,0 ± 0,2 min/μm of anodic oxidation coating thickness.
12.8.6 Other sealing systems
Other sealing systems including medium-temperature sealing that have been approved by
Qualanod shall be used in accordance with the suppliers’ written instructions.
12.9 Methods for process control
12.9.1 Etching
Alkaline etching baths shall be analysed in accordance with the instructions of the supplier of
the etch chemicals. In the absence of such instructions, the analyses of free sodium
hydroxide, aluminium and, if appropriate, the sequestrant shall be carried out. The analysis
frequency shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day.
• once every day the line is in use if the bath is in a coil anodizing line.
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Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each etching bath shall be checked at regular intervals and at least twice
during every work shift when the line is in use. It shall be checked at the beginning of an etch
cycle.
12.9.2 Brightening
Brightening baths shall be analysed in accordance with the instructions of the supplier of the
brightening chemicals. The analysis frequency shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day;
• once every day the line is in use if the bath is in a coil anodizing line.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each brightening bath shall be checked at regular intervals and at least
twice during every work shift when it is being used. It shall be checked at the beginning of a
brightening cycle.
12.9.3 Anodizing
Anodizing baths shall be analysed in accordance with the instructions of the supplier of any
anodizing additive. In the absence of such instructions, the analysis of free sulfuric acid and
dissolved aluminium shall be carried out. The analysis frequency shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day;
• once every day the line is in use if the bath is in a coil anodizing line.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each anodizing bath shall be checked at regular intervals and at least
twice during every work shift when the line is in use. It shall be checked at the end of an
anodizing cycle.
12.9.4 Sealing
Sealing baths, including all baths of multi-step sealing procedures, shall be analysed in
accordance with the instructions of the suppliers of the sealing chemicals.
For cold sealing, the free fluoride and nickel content of the bath shall be checked at least once
per shift when the line is in use. Based on the results of the analysis the bath composition
shall be adjusted accordingly.
The pH value of all sealing baths, including all baths of multi-step sealing procedures, shall be
measured at regular intervals and at least twice during every work shift when the line is in use.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each sealing bath shall be checked at regular intervals and at least twice
during every work shift when the line is in use. It shall be checked 10 minutes after the
immersion of a load.
12.9.5 Storage of products
Aluminium products shall be stored away from the anodizing facilities both before and after
anodizing. After anodizing, they shall be protected from condensation and dirt. Every
anodized part in stock shall be marked with the coating thickness.
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12.10 Production control records
12.10.1 Control system
The anodizing plant shall have a secure system for controlling production and its records shall
show at least the following information.
•
•
•
•
•
•
•
•
•
The customer's name and address, order or serial number.
The production date.
The kind of anodizing (clear or coloured).
The agreed coating thickness class and the actual thickness measured (minimum and
maximum values of average and local thicknesses).
The results of the mass loss test.
Where applicable, the results of the dye spot test or admittance test.
Where applicable, the results of the surface abrasion resistance test.
Where applicable, evidence that the colouring technique conforms to 12.7.12.
Measures taken to remedy values not meeting the requirements.
The records shall include the following.
•
•
•
•
The results of analyses and temperature monitoring of etch baths, and the number of
shifts worked.
The results of analyses and temperature monitoring of anodizing baths, and the
number of shifts worked.
The product name and application of any proprietary chemicals or processes used, for
example in sealing.
The results of analyses and temperature and pH monitoring of sealing baths.
All the information shall be readily accessible for the inspector.
12.10.2 Traceability
The licensee shall specify and maintain procedures to associate the production clearly with
the pertinent drawings, specifications or other documents during all phases of production,
delivery and assembly. Individual products, lots or batches shall be identified unmistakably.
This identification shall be included in the control system records.
12.11 Inspections
12.11.1 General
The inspector carries out inspections as described in clause 8 with reference to the
requirements included here in 12.11. In order to avoid an unproductive inspection visit, it is
advisable that the plant notifies the appropriate body if it is concerned that sufficient material
for testing might not be available during certain periods.
12.11.2 Identification of parts passed by internal quality control
The licensee shall indicate to the Qualanod inspector which goods have passed the internal
quality control. Goods that are kept in stock ready for dispatch or packed shall be considered
to have passed the internal quality control.
The licensee shall clearly identify parts not covered by his licence for architectural anodizing.
The inspector may seek verification of the type of anodizing by, for example, examining the
written agreement between the anodizer and his customer.
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12.11.3 The product tests of an inspection
The following product tests can be carried out during an inspection or at the testing institute.
• Coating thickness
• Mass loss
• Dye spot or admittance (admittance tests are carried out within 48 h after sealing)
• Surface abrasion resistance
The applicability to the products and the acceptance criteria are the same as those given in
12.7. Note that for the purposes of an inspection, all the tests have equal significance; the
concept of a referee test is not applicable.
12.11.4 Processes
The inspector verifies that the processes are carried out in compliance with the requirements
of 12.8. He also verifies by observation that bath analyses are performed correctly.
If a licensee does not want a particular anodizing line to be included in the inspection, he shall
provide evidence to the inspector that it is not used for architectural anodizing. Production
control records can provide such evidence.
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Appendix - Industrial anodizing
13.1 Introduction
Clauses 2 to 9 contain general provisions that apply irrespective of the type of anodizing. The
following are particularly significant.
• Clause 6. Granting and renewing licences.
• Clause 7. Regulations for the use of the Qualanod label.
• Clause 8. Inspections.
• Clause 9. Test methods for products.
13.2 Scope
This clause specifies requirements for industrial anodizing and products produced by industrial
anodizing where appearance is secondary or of no importance.
Industrial anodizing produces anodic oxidation coatings that are mainly used to obtain:
• resistance to wear through abrasion or erosion;
• electrical insulation;
• thermal insulation;
• build-up (to repair parts out of tolerance on machining or worn parts);
• resistance to corrosion (when sealed).
There are many products for automotive, medical or kitchen applications where appearance
is not insignificant but much more important are resistance to wear processes and/or cleaning
using aggressive chemical agents. In such cases, these are particularly demanding of the
properties of anodized aluminium.
However, where appearance and protection are of comparable importance, the provisions of
clause 12, architectural anodizing, shall apply.
Further, where high quality wear resistance is the primary characteristic, the provisions of
clause 15, hard anodizing, shall apply.
13.3 Quality label
The use of the quality label shall comply with the requirements of clause 7.
13.4 Agreements with customers
13.4.1 Information to be supplied by the customer
The following information shall be supplied, when appropriate, by the customer to the licensee,
if necessary in consultation with the aluminium supplier or the licensee or both.
• The specification of the aluminium to be anodized (alloy and temper).
• The extent of the significant surface(s) of the article to be anodized.
• The anodic oxidation coating thickness required.
• The final dimensional tolerances, if required.
• The preferred positions and dimensions of the contact (jigging) marks.
• Any special requirements for surface preparation, eg shot-peening, etching, grinding.
• Any special requirements for post-treatment, eg sealing, impregnation, grinding.
• Any special characteristic required, such as wear resistance, corrosion resistance,
microhardness.
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13.4.2 The aluminium to be anodized
Recommendations for the selection of alloys are given in clause 11.
The properties and characteristics of anodic oxidation coatings are significantly affected by
both the alloy and the method of production. Consequently, materials are classified into five
alloy groupings as follows:
• Class 1: all wrought alloys except those of the 2000 series and class 2b;
• Class 2a: alloys of the 2000 series containing less than 5 % copper;
• Class 2b: alloys of the 5000 series containing 2 % or more magnesium and alloys of
the 7000 series;
• Class 3a: casting alloys with less than 2 % copper and/or 8 % silicon;
• Class 3b: other casting alloys.
13.4.3 Significant surfaces
Significant surfaces are indicated preferably by drawings or by suitably marked samples; in
some cases, there can be different requirements for the finish on different parts of the
significant surface(s). Masking can be necessary to enable different requirements to be
achieved.
13.4.4 Thickness grade
Anodic oxidation coatings may be graded by thickness class or nominal thickness. Thickness
class is determined by the minimum allowed values of the average thickness and the local
thickness. The thickness classes are designated by the letters “AA”. The definitions of typical
thickness classes are given in Table 13-1. Some guidance on nominal thicknesses is
given in clause 11.
Table 13-1. Typical thickness classes
Thickness class
Minimum average thickness
(μm)
Minimum local thickness
(μm)
AA10
10
8
AA15
15
12
AA20
20
16
AA25
25
20
13.4.5 Surface preparation
ISO 7599 includes a surface preparation designation system.
13.4.6 Final dimensional tolerances
Anodizing leads to an increase in the dimensions of an article, which is equal to about 50% of
the coating thickness for each anodized surface.
13.5 Complaints
Any complaints by customers to anodizers should be made in writing. The anodizer shall
maintain a register of complaints which includes actions taken
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13.6 Laboratory and testing apparatus
13.6.1 Laboratory
The anodizing plant shall have laboratory facilities.
13.6.2 Apparatus
13.6.2.1 General
Each apparatus shall conform to the requirements of the appropriate standard for the test
concerned. Each apparatus shall be functional. Each piece of apparatus shall have a data
sheet showing the apparatus identification number and calibration checks.
13.6.2.2 Apparatus for product testing
The anodizing plant shall have at least two instruments for measuring thickness using the
eddy current method or one instrument for the eddy current method and one split-beam optical
microscope (9.2).
As required, the anodizing plant shall have the following equipment to carry out the mass loss
test (9.3):
• analytical balance (precision 0.1 mg)
• drying oven
• desiccator
• heating device
• means of agitating the solution
• chemical products
As required, the anodizing plant shall have solutions available to carry out the dye spot test
(9.3.3).
The anodizing plant shall have access to apparatus to carry out any other product tests
described in 13.7 that are required by the customer.
13.6.2.3 Apparatus for testing baths
The anodizing plant laboratory shall have a pH meter and two buffer solutions.
13.7 Product tests to be applied by the licensee
Some subclauses in this section are omitted on purpose.
13.7.1 Required tests
The licensee shall apply the following product quality tests depending on the products it
produces. See below for details.
• Thickness
• Visible defects
Additionally, the licensee shall apply any of the tests described below that are required by the
customer.
If it is not possible to take and test specimens from the production lot because of the shape,
size or form of the product, the licensee may carry out tests on specimens made of the same
alloy as the production lot and treated simultaneously with it. This shall be recorded in the
production control system.
The licensee shall have the standards specifying the tests that it applies. The standards are
identified in clause 4.
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13.7.2 Thickness and dimensional tolerances
Thickness measurements shall be made using a method of 9.2.
When a thickness class is specified, the average thickness and the local thickness shall not
be lower than the minimum values for the specified thickness class.
Where a nominal thickness of up to 50 µm is specified, the average thickness shall not be
outside ± 20% of the nominal thickness. Where a nominal thickness over 50 µm is specified,
the average thickness shall not be outside ±10 µm of the nominal thickness.
The measurement of thickness or, where relevant, final dimensions shall be dealt with in a lot
acceptance test.
13.7.3 Sealing quality
13.7.3.1 Mass loss test
If required by the customer, anodized products shall be assessed using the method of 9.3.1
and the mass loss shall not exceed 30 mg/dm2.
The mass loss test shall be carried out at least:
• once a day for each sealing bath if colour-anodized products represent 100% of total
output in the week;
• once every two days for each sealing bath if colour-anodized products represent more
than 50% and less than 100% of total output in the week;
• once a week for each sealing bath if colour anodized products represent less than 50%
of total output in the week;
• once a day for each coil-anodizing line that is in use.
13.7.3.2 Dye spot test
If required by the customer, anodized products shall be assessed using the method of 9.3.3.
The rating shall not exceed 2.
The dye spot test shall be carried out at least once for each sealing bath in every work shift.
For coil-anodizing lines, the dye spot test shall be carried out at least once on every coil.
13.7.4 Visible defects
Parts shall be examined visually in compliance with 9.4.1. The significant surface shall be
completely anodized. The visual appearance shall be substantially uniform without spalling,
blistering or powdery (burnt) areas. Crazing or microcracks are not normally a reason for
rejection.
13.7.5 Surface texture and colour
If required by the customer, the surface texture and colour of anodized components shall be
within the permissible limits agreed by the licensee and the customer.
13.7.7 Corrosion resistance
If required by the customer, the corrosion resistance shall be assessed using one of the
methods of 9.5.
After the NSS test, a test specimen with an anodic oxidation coating thickness of 50 μm shall
not show any corrosion pits except those within 1.5 mm of jigging marks or corners.
The AASS test shall be carried out using reference specimens so the comparative
performance of the test specimens can be assessed. This may involve the examination of
specimens at intermediate times during the test. The rating of corroded specimens shall be
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decided using one of the systems specified in ISO 8993 and ISO 8994. The acceptance
criteria for the AASS test shall be agreed by the licensee and the customer.
These tests are only applicable to sealed oxidation coatings.
13.7.9 Wear resistance
If required by the customer, the wear resistance of anodic oxidation coatings shall be
determined by using either the abrasive wheel method of 9.6.2 or the abrasive jet method of
9.6.3. The selection of the method and the procedure shall comply with ISO 10074.
The time between anodizing and testing shall be at least 24 h. During this period, the test
pieces shall be stored in the test environment.
The test frequency shall be agreed by the licensee and the customer.
The resistance to wear shall have the values given in Table 13-2.
Table 13-2. Acceptance values for wear tests
Material class
Number of double
strokes (abrasive
wheel method)
Minimum relative
mean specific
abrasion resistance
(abrasive wheel and
abrasive jet
methods)
Maximum mass
loss (Taber
method)
Class 1
Class 2 (a)
Class 2 (b)
Class 3 (a)
Class 3 (b)
800 to 100
400 to 100
800 to 100
400 to 100
400 to 100
80%
30%
55%
55%
20%
15 mg
35 mg
25 mg
13.7.10 Microhardness
If required by the customer, the microhardness of anodic oxidation coatings shall be
determined by using the Vickers microhardness method of. 9.7. The test load shall be 0.49 N
for material classes 1, 2a, 2b and 3a. The test load for material class 3b shall be agreed by
the licensee and the customer.
The test frequency and the acceptance criterion shall be agreed by the licensee and the
customer. In the absence of such an agreement, anodic oxidation coatings with a thickness
of 25 μm to 50 μm shall have the minimum microhardness values given in Table 13-3.
Table 13-3. Acceptance values for the Vickers microhardness test
Material class
Minimum acceptable value (Hv 0,05)
Class 1
Class 2 (a)
Class 2 (b)
Class 3 (a)
400
250
300
250
13.7.11 Resistance to cracking by deformation
If required by the customer, anodized rolled-products shall be assessed for resistance to
cracking by deformation using the method of 9.8. The test frequency and the acceptance
criterion shall be agreed by the licensee and the customer.
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Assessing resistance to deformation can be relevant for rolled products that are deformed
after anodizing.
13.7.13 Electrical breakdown potential
If required by the customer, the electrical breakdown potential shall be determined using the
method of 9.10.
The test frequency and the acceptance criterion shall be agreed by the licensee and the
customer. In the absence of such an agreement, anodic oxidation coatings 50 µm thick on
alloys containing less than 1 % copper shall have a minimum breakdown voltage of 1200 V
and other alloys shall have a minimum breakdown voltage of 800 V. These values shall be
the mean values of ten measurements.
13.7.14 Coating continuity
If required by the customer, coil-anodized products shall be assessed for coating continuity
using the method of 9.11. After the test, visual examination shall reveal no black and/or dark
reddish spots on the surface of the specimen.
The coating continuity test shall be carried out once a day for each coil-anodizing line that is
in use.
13.7.15 Surface density
If required by the customer, the surface density shall be determined using the method of 9.12.
The test frequency and the acceptance criterion shall be agreed by the licensee and the
customer. In the absence of such an agreement, the surface density shall be at least 1100
mg/dm2 for a 50 µm thick coating or equivalent for coatings of other thicknesses.
13.7.17 Roughness
If required by the customer, the method, test frequency and acceptance criterion shall be
agreed by the licensee and the customer.
13.7.18 Service simulation tests
If required by the customer, anodized products shall be assessed using a test or tests specified
by the customer to simulate the service conditions. The test frequency and the acceptance
criterion shall be agreed by the licensee and the customer.
13.8 Requirements concerning processes
13.8.1 Anodizing
Anodizing shall be carried out using solutions based on sulfuric acid.
13.8.2 Colouring
Instructions from suppliers of dyes shall be followed.
The instructions from suppliers of electrolytic colouring processes shall be followed. For
external applications, the quality label shall not be used for black finishes produced using
electrolytic colouring with solutions based on copper salts.
13.8.3 Sealing process
The instructions from suppliers of sealing chemicals shall be followed.
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13.8.4 Hot water sealing
For hot water sealing, the temperature shall not be below 96 °C 10 minutes after immersion
of the load.
13.8.5 Cold sealing.
13.8.5.1 General
The provisions of this section shall be adopted for two-step cold sealing using solutions
containing nickel fluoride.
13.8.5.2 First step of cold sealing
The nickel ion content of the solution shall be maintained at 1,5 ± 0,3 g/l. 5 - 10% of the nickel
may be substituted by cobalt.
The free fluoride ion content of the solution shall be maintained at the level specified by the
supplier of the cold sealing product.
The solution shall be maintained at a temperature between 25 °C and 30 °C.
The pH of the solution shall be maintained between 5,8 and 7,0.
The immersion time shall be 1,0 ± 0,2 min/μm of anodic oxidation coating thickness.
13.8.5.3 Second step of cold sealing
The solution shall comprise either tap water containing 4,0 ± 1,0 g/l nickel sulfate or nickel
acetate, or deionized water containing an antismut additive.
The solution shall be maintained at a temperature of at least 60 °C (preferably 70°C).
The immersion time shall be 1,0 ± 0,2 min/μm of anodic oxidation coating thickness.
13.8.6 Other sealing systems
Other sealing systems including medium-temperature sealing shall be used in accordance
with the suppliers’ written instructions.
13.9 Methods for process control
13.9.1 Etching
If requirements for the surface texture of anodized components are the subject of an
agreement between the licensee and the customer, then the following shall apply.
Alkaline etching baths shall be analysed in accordance with the instructions of the supplier of
the etch chemicals. In the absence of such instructions, the analysis of total sodium hydroxide,
aluminium and, if appropriate, the sequestrant shall be carried out. The analysis frequency
shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day.
• once every day the line is in use if the bath is in a coil anodizing line.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each etching bath shall be checked at regular intervals and at least twice
during every work shift when the line is in use. It shall be checked at the beginning of an etch
cycle.
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13.9.2 Brightening
Brightening baths shall be analysed in accordance with the instructions of the supplier of the
brightening chemicals. The analysis frequency shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day;
• once every day the line is in use if the bath is in a coil anodizing line.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each brightening bath shall be checked at regular intervals and at least
twice during every work shift when it is being used. It shall be checked at the beginning of a
brightening cycle.
13.9.3 Anodizing
Anodizing baths shall be analysed in accordance with the instructions of the supplier of any
anodizing additive. In the absence of such instruction, the analysis of free sulfuric acid and
dissolved aluminium shall be carried out. The analysis frequency shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day;
• once every day the line is in use if the bath is in a coil anodizing line.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each anodizing bath shall be checked at regular intervals and at least
twice during every work shift that the line is in use. It shall be checked at the end of an
anodizing cycle.
13.9.4 Sealing
Sealing baths, including all baths of multi-step sealing procedures, shall be analysed in
accordance with the instructions of the suppliers of the sealing chemicals.
For cold sealing, the free fluoride and nickel content of the bath shall be checked at least once
per shift when the line is in use. Based on the results of the analysis the bath composition
shall be adjusted accordingly.
The pH value of all sealing baths, including all baths of multi-step sealing procedures, shall be
measured at regular intervals and at least twice during every work shift when the line is in use.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each sealing bath shall be checked at regular intervals and at least twice
during every work shift when the line is in use. It shall be checked 10 minutes after the
immersion of a load.
13.9.5 Storage of products
Aluminium products shall be stored away from the anodizing facilities both before and after
anodizing. After anodizing, they shall be protected from condensation and dirt.
13.10 Production control records
13.10.1 Control systems
The anodizing plant shall have a secure system for controlling production and its records shall
show at least the following information.
• The customer’s name and address, order or serial number;
• The production date;
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•
•
The agreed coating thickness and the actual thickness measured (minimum and
maximum values of average thickness);
The results of all other tests required by the customer;
Measures taken to remedy values not meeting the requirements.
The records shall include the following.
• The results of analyses and temperature monitoring of anodizing baths, and the
number of shifts worked.
• The product name and application of any proprietary chemicals or processes used, for
example in sealing.
• The results of analyses and temperature and pH monitoring of sealing baths.
All the information shall be readily accessible for the inspector.
13.10.2 Traceability
The licensee shall specify and maintain procedures to associate the production clearly with
the pertinent drawings, specifications or other documents during all phases of production,
delivery and assembly. Individual products, lots or batches must be identified unmistakably.
This identification shall be included in the control system records.
13.11 Inspections
13.11.1 General
The inspector carries out inspections as described in clause 8 with reference to the
requirements included here in 13.11. In order to avoid an unproductive inspection visit, it is
advisable that the plant notifies the appropriate body if it is concerned that sufficient material
for testing might not be available during certain periods.
13.11.2 Identification of parts passed by internal quality control
The licensee shall indicate to the Qualanod inspector which goods have passed the internal
quality control. Goods that are kept in stock ready for dispatch or packed shall be considered
to have passed the internal quality control.
The licensee shall clearly identify parts not covered by his licence for industrial anodizing. The
inspector may seek verification of the type of anodizing by, for example, examining the written
agreement between the anodizer and his customer.
13.11.3 The product tests of an inspection
The following product tests can be carried out during an inspection or at the testing institute.
• Coating thickness
• Mass loss
• Dye spot test
• Final dimensions
The applicability to the products and the acceptance criteria are the same as those given in
13.7. Note that for the purposes of an inspection, all the tests have equal significance; the
concept of a referee test is not applicable.
13.11.4 Processes
The inspector verifies that the processes are carried out in compliance with the requirements
of 13.8. He also verifies by observation that bath analyses are performed correctly.
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If a licensee does not want a particular anodizing line to be included in the inspection, he shall
provide evidence to the inspector that it is not used for industrial anodizing. Production control
records can provide such evidence.
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Appendix - Decorative anodizing
14.1 Introduction
Clauses 2 to 9 contain general provisions that apply irrespective of the type of anodizing. The
following are particularly significant.
• Clause 6. Granting and renewing licences.
• Clause 7. Regulations for the use of the Qualanod label.
• Clause 8. Inspections.
• Clause 9. Test methods for products.
14.2 Scope
This clause specifies requirements for decorative anodizing and products produced by
decorative anodizing.
Decorative anodizing is defined in ISO 7583 as “anodizing to produce a decorative finish with
a uniform or aesthetically pleasing appearance as the primary characteristic”.
Examples are shower screens, lipstick holders and lighting reflectors.
14.3 Quality label
The use of the quality label shall comply with the requirements of clause 7.
14.4 Agreements with customers
14.4.1 Information to be supplied by the customer
The following information shall be supplied by the customer to the licensee, if necessary in
consultation with the aluminium supplier or the licensee or both.
• The intended service use of the article to be anodized.
• The specification of the aluminium to be anodized (alloy and temper).
• The extent of the significant surface(s) of the article to be anodized.
• The anodic oxidation coating thickness required.
• Any preferred positions and dimensions of the contact (jigging) marks.
• The surface preparation to be used on the aluminium before anodizing and the limits
of variation of the final surface finish.
• The colour of the anodized article and the maximum limits of colour variation.
• The sealing method to be used.
14.4.2 The aluminium to be anodized
Recommendations on the selection of alloys are given in clause 11.
14.4.3 Significant surfaces
Significant surfaces are indicated preferably by drawings or by suitably marked samples. In
some cases, there can be different requirements for the finish on different parts of the
significant surface(s).
14.4.4 Thickness grade
Anodic oxidation coatings are graded by thickness class which is determined by the minimum
allowed values of the average thickness and the local thickness. The thickness grades are
designated by the letters “AA”. The definitions of typical thickness grades are given in Table
14-1.
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Table 14-1. Typical thickness grades
Minimum average
thickness (μm)
Minimum local thickness
(μm)
AA3
3
Not specified
AA5
5
4
AA10
10
8
AA15
15
12
Thickness grade
14.4.5 Surface preparation
The surface preparation is indicated preferably by means of reference specimens that are
acceptable to both parties.
14.4.6 Colour
The permissible colour variation is indicated preferably by means of reference specimens that
are acceptable to both parties. The specimens can represent agreed darkest and lightest
limits.
14.5 Complaints
Any complaints by customers to anodizers should be made in writing. The anodizer shall
maintain a register of complaints which includes actions taken
14.6 Laboratory and testing apparatus
14.6.1 Laboratory
The anodizing plant shall have laboratory facilities.
14.6.2 Apparatus
14.6.2.1 General
Each apparatus shall conform to the requirements of the appropriate standard for the test
concerned. Each piece of apparatus shall be functional and have a data sheet showing the
apparatus identification number and calibration checks.
14.6.2.2 Apparatus for product testing
Each anodizing plant shall have at least two instruments for measuring thickness using the
eddy current method or one instrument for the eddy current method and one split-beam optical
microscope (9.2).
The anodizing plant shall have the following equipment to carry out the mass loss test (9.3.1
or 9.3.2):
• analytical balance (precision 0.1 mg)
• drying oven
• desiccator
• heating device
• means of agitating the solution
• chemical products
If the anodizing plant uses the dye spot test, it shall have solutions available to carry out the
test (9.3.3).
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If the anodizing plant uses the admittance test, it shall have at least one instrument for
measuring admittance and a reference unit for checking the reading accuracy of the device
(9.3.4).
The anodizing plant shall have access to apparatus to carry out any other product tests
described in 14.7 that are required by the customer.
14.6.2.3 Apparatus for testing baths
The anodizing plant laboratory shall have a pH meter and two buffer solutions.
14.7 Product tests to be applied by the licensee
Some subclauses in this section are omitted on purpose.
14.7.1 Required tests
The licensee shall apply the following product quality tests depending on the products it
produces. See below for details.
• Thickness
• Mass loss test
• Either the dye spot test or the admittance test or both
• Assessment for visible defects, surface texture and, if appropriate, colour
Additionally, the licensee shall apply any of the tests described below that are required by the
customer.
If it is not possible to take and test specimens from the production lot because of the shape,
size or form of the product, the licensee may carry out tests on specimens made of the same
alloy as the production lot and treated simultaneously with it. This shall be recorded in the
production control system.
The licensee shall have the standards specifying the tests that it applies. The standards are
identified in clause 4.
14.7.2 Thickness
Average and local coating thicknesses shall be measured on products using a method
specified in 9.2. These shall not be lower than the minimum values for the specified thickness
class.
14.7.3 Sealing quality
14.7.3.1 Mass loss test
Anodized products shall be assessed using the method of 9.3.1 or 9.3.2 and the mass loss
shall not exceed 30 mg/dm2. The method shall be agreed by the licensee and the customer.
This shall be the referee test for sealing quality.
The mass loss test shall be carried out at least:
• once a day for each sealing bath if colour-anodized products represent 100% of total
output in the week;
• once every two days for each sealing bath if colour-anodized products represent more
than 50% and less than 100% of total output in the week;
• once a week for each sealing bath if colour anodized products represent less than 50%
of total output in the week;
• once a day for each coil-anodizing line that is in use.
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14.7.3.2 Dye spot test
Anodized products shall be assessed using the method of 9.3.3. The rating shall not exceed
2. If the rating is 2, either a mass loss test shall be carried out or the sealing shall be repeated.
This is a production control test for sealing quality. It is an acceptance test for the absorptivity
of an anodized surface.
The dye spot test shall be carried out at least once for each sealing bath in every work shift.
For coil-anodizing lines, the dye spot test shall be carried out at least once on every coil.
14.7.3.3 Admittance test
Anodized products shall be assessed using the method of 9.3.4. The acceptance limit for the
corrected admittance shall be 20 µS. If the corrected admittance exceeds 20 μS, either a
mass loss test shall be carried out or the sealing shall be repeated. The acceptance limit for
the admittance is not applicable to electrolytically coloured parts in medium bronze, dark
bronze and black. Those are finishes with an L* value less than about 60 on the CIE 1976 L*
a* b* scale.
This is a production control test.
The admittance test shall be carried out at least once for each sealing bath in every work shift.
It is not necessary to carry out admittance tests on coil-anodized products.
14.7.4 Visible defects
Anodized parts shall be taken using a sampling scheme agreed by the interested parties. The
anodized parts shall be free from visible defects on the significant surface(s) when viewed
from a distance agreed by the interested parties. In the absence of such agreements, the
visual examination shall comply with 9.4.1 and the following viewing distances shall apply.
• 2 m for internal architectural applications
• 0,5 m for decorative articles
The metal received by the licensee shall be of sufficient quality to be free of visible defects,
depending on the customer’s requirements, on significant surfaces after processing through
the anodizing line. If there is doubt or dispute whether processing through the anodizing line
would sufficiently reduce the visibility of defects or rolling or die lines, the ability to remove or
mask them shall be assessed by treating a specimen of the metal through the anodizing line
to produce the agreed finish and then by visual evaluation as described above.
14.7.5 Surface texture and colour
The surface texture and colour of anodized components and reference specimens shall be
assessed in compliance with 9.4.2. They shall be viewed from a distance agreed by the
interested parties. In the absence of such an agreement, the following viewing distances shall
apply.
• Those described in 14.7.4 for the comparison of anodized components
• 0,5 m for the comparison of anodized components with reference specimens agreed
by the interested parties
The surface texture and colour of anodized components shall be within the permissible limits
agreed by the licensee and the customer.
Agreed reference specimens shall be stored in a dry place in the dark.
14.7.6 Light reflection properties
If required by the customer, light reflection properties shall be assessed following 9.4.3. The
test frequency and acceptance criteria shall be agreed by the licensee and the customer.
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14.7.9 Wear resistance
If required by the customer, anodized products shall be assessed for bulk wear resistance
using method 9.6.2, 9.6.3 or 9.6.4. The method, the test frequency and the acceptance
criterion shall be agreed by the licensee and the customer.
Assessing wear resistance can be relevant for products that are regularly handled by a user.
14.7.11 Resistance to cracking by deformation
If required by the customer, anodized rolled-products shall be assessed for resistance to
cracking by deformation using the method of 9.8. The test frequency and the acceptance
criterion shall be agreed by the licensee and the customer.
Assessing resistance to deformation can be relevant for rolled products that are deformed
after anodizing.
14.7.12 Light fastness and resistance to ultraviolet radiation
If required by the customer, anodic oxidation coatings shall be assessed for light fastness
using the method of 9.9.1. The test frequency and acceptance criterion shall be agreed by
the licensee and the customer.
Note. It has been demonstrated that electrolytically-coloured anodized aluminium conforms
to the specification for light fastness.
If required by the customer, anodic oxidation coatings shall be assessed for resistance to
ultraviolet radiation using the method of 9.9.2. The test frequency and acceptance criterion
shall be agreed by the licensee and the customer.
14.7.14 Coating continuity
If required by the customer, coil-anodized products shall be assessed for coating continuity
using the method of 9.11. After the test, visual examination shall reveal no black and/or dark
reddish spots on the surface of the specimen.
The coating continuity test shall be carried out once a day for each coil-anodizing line that is
in use.
14.7.16 Thermal craze resistance
If required by the customer, anodized products shall be assessed for resistance to thermal
crazing using the method of 9.13. The test frequency and the acceptance criterion shall be
agreed by the licensee and the customer. In the absence of such an agreement, no crazing
shall be visually apparent on anodic oxidation coatings treated at a metal temperature below
80°C.
14.7.18 Service simulation tests
If required by the customer, anodized products shall be assessed using a test or tests specified
by the customer to simulate the service conditions. The test frequency and the acceptance
criterion shall be agreed by the licensee and the customer.
14.8 Requirements concerning processes
14.8.1 Anodizing
Anodizing shall be carried out using solutions based on sulfuric acid.
14.8.2 Colouring
The instructions from suppliers of dyes shall be followed.
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The instructions from suppliers of electrolytic colouring processes shall be followed.
14.8.3 Sealing process
The instructions from suppliers of sealing chemicals shall be followed.
14.8.4 Hot water sealing
For hot water sealing, the temperature shall not be below 96 °C 10 minutes after immersion
of the load.
14.8.5 Cold sealing.
14.8.5.1 General
The provisions of this section shall be adopted for two-step cold sealing using solutions
containing nickel fluoride.
14.8.5.2 First step of cold sealing
The nickel ion content of the solution shall be maintained at 1,5 ± 0,3 g/l. 5 - 10% of the nickel
may be substituted by cobalt.
The free fluoride ion content of the solution shall be maintained at the level specified by the
supplier of the cold sealing product.
The solution shall be maintained at a temperature between 25 °C and 30 °C.
The pH of the solution shall be maintained between 5,8 and 7,0.
The immersion time shall be 1,0 ± 0,2 min/μm of anodic oxidation coating thickness.
14.8.5.3 Second step of cold sealing
The solution shall comprise either tap water containing 4,0 ± 1,0 g/l nickel sulfate or nickel
acetate, or deionized water containing an antismut additive.
The solution shall be maintained at a temperature of at least 60 °C.
The immersion time shall be 1,0 ± 0,2 min/μm of anodic oxidation coating thickness.
14.8.6 Other sealing systems
Other sealing systems including medium-temperature sealing systems shall be used in
accordance with the suppliers’ written instructions.
14.9 Methods for process control
14.9.1 Etching
Alkaline etching baths shall be analysed in accordance with the instructions of the supplier of
the etch chemicals. In the absence of such instructions, the analysis of total sodium hydroxide,
aluminium and, if appropriate, the sequestrant shall be carried out. The analysis frequency
shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day;
• once every day the line is in use if the production is from a coil anodizing line.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each etching bath shall be checked at regular intervals and at least twice
during every work shift that the line is in use. It shall be checked at the beginning of an etch
cycle.
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14.9.2 Brightening
Brightening baths shall be analysed in accordance with the instructions of the supplier of the
brightening chemicals. The analysis frequency shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day;
• once every day the line is in use if the bath is in a coil anodizing line.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each brightening bath shall be checked at regular intervals and at least
twice during every work shift when it is being used. It shall be checked at the beginning of a
brightening cycle.
14.9.3 Anodizing
Anodizing baths shall be analysed in accordance with the instructions of the supplier of any
anodizing additive. In the absence of such instructions, the analysis of free sulfuric acid and
dissolved aluminium shall be carried out. The analysis frequency shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day;
• once every day the line is in use if the bath is in a coil anodizing line.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each anodizing bath shall be checked at regular intervals and at least
twice during every work shift that the line is in use. It shall be checked at the end of an
anodizing cycle.
14.9.4 Sealing
Sealing baths, including all baths of multi-step sealing procedures, shall be analysed in
accordance with the instructions of the suppliers of the sealing chemicals.
For cold sealing, the free fluoride and nickel content of the bath shall be checked at least once
per shift when the line is in use. Based on the results of the analysis the bath composition
shall be adjusted accordingly.
The pH value of all sealing baths, including all baths of multi-step sealing procedures, shall be
measured at regular intervals and at least twice during every work shift when the line is in use.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each sealing bath shall be checked at regular intervals and at least twice
during every work shift when the line is in use. It shall be checked 10 minutes after the
immersion of a load.
14.9.5 Storage of products
Aluminium products shall be stored away from the anodizing facilities both before and after
anodizing. After anodizing, they shall be protected from condensation and dirt. Every
anodized part in stock shall be marked with the coating thickness.
14.10 Production control records
14.10.1 Control system
The anodizing plant shall have a secure system for controlling production and its records shall
show at least the following information.
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The customer's name and address, order or serial number;
The production date;
The kind of anodizing (clear or coloured);
The agreed coating thickness class and the actual thickness measured (minimum and
maximum values of average and local thicknesses);
The results of the mass loss test;
Where applicable, the results of the dye spot test or admittance test;
The results of all other tests required by the customer;
Measures taken to remedy values not meeting the requirements.
The records shall include the following.
• The results of analyses and temperature monitoring of etch baths, and the number of
shifts worked.
• The results of analyses and temperature monitoring of brightening baths, and the
number of shifts worked.
• The results of analyses and temperature monitoring of anodizing baths, and the
number of shifts worked.
• The product name and application of any proprietary chemicals or processes used, for
example in sealing.
• The results of analyses and temperature and pH monitoring of sealing baths.
All the information shall be readily accessible for the inspector.
14.10.2 Traceability
The licensee shall specify and maintain procedures to associate the production clearly with
the pertinent drawings, specifications or other documents during all phases of production,
delivery and assembly. Individual products, lots or batches must be identified unmistakably.
This identification shall be included in the control system records.
14.11 Inspections
14.11.1 General
The inspector carries out inspections as described in clause 8 with reference to the
requirements included here in 14.11. In order to avoid an unproductive inspection visit, it is
advisable that the plant notifies the appropriate body if it is concerned that sufficient material
for testing might not be available during certain periods.
14.11.2 Identification of parts passed by internal quality control
The licensee shall indicate to the Qualanod inspector which goods have passed the internal
quality control. Goods that are kept in stock ready for dispatch or packed shall be considered
to have passed the internal quality control.
The licensee shall clearly identify parts not covered by his licence for decorative anodizing.
The inspector may seek verification of the type of anodizing by, for example, examining the
written agreement between the anodizer and his customer.
14.11.3 The product tests of an inspection
The following product tests can be carried out during an inspection or at the testing institute.
• Coating thickness
• Mass loss
• Dye spot or admittance (admittance tests are carried out within 48 h after sealing)
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The applicability to the products and the acceptance criteria are the same as those given in
14.7. Note that for the purposes of an inspection, all the tests have equal significance; the
concept of a referee test is not applicable.
14.11.4 Processes
The inspector verifies that the processes are carried out in compliance with the requirements
of 14.8. He also verifies by observation that bath analyses are performed correctly.
If a licensee does not want a particular anodizing line to be included in the inspection, he shall
provide evidence to the inspector that it is not used for decorative anodizing. Production
control records can provide such evidence.
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Appendix - Hard anodizing
15.1 Introduction
Clauses 2 to 9 contain general provisions that apply irrespective of the type of anodizing. The
following are particularly significant.
• Clause 6. Granting and renewing licences.
• Clause 7. Regulations for the use of the Qualanod label.
• Clause 8. Inspections.
• Clause 9. Test methods for products.
15.2 Scope
This clause specifies requirements for hard anodizing and products produced by hard
anodizing.
Hard anodizing is defined in ISO 7583 as “anodizing to produce a coating where high wear
resistance or microhardness is its primary characteristic”.
Examples of hard anodized products can be valves, sliding parts, hinge mechanisms, cams,
gears, swivel joints, pistons, pulleys, valve blocks, rod ends and food chutes.
15.3 Quality label
The use of the quality label shall comply with the requirements of clause 7.
15.4 Agreements with customers
15.4.1 Information to be supplied by the customer
The following information shall be supplied, when appropriate, by the customer to the licensee,
if necessary in consultation with the aluminium supplier or the licensee or both.
• The specification of the aluminium to be anodized (alloy and temper).
• The extent of the significant surface(s) of the article to be anodized.
• The anodic oxidation coating thickness required.
• The final dimensional tolerances.
• The preferred position and dimensions of the contact (jigging) marks.
• Any special requirements for surface preparation, eg shot-peening, etching, grinding.
• Any special requirements for post-treatment, eg impregnation, grinding, sealing.
• Any special characteristic required, such as corrosion resistance, electrical breakdown
potential and electrical insulation.
15.4.2 The aluminium to be anodized
Recommendations for the selection of alloys are given in clause 11.
15.4.3 Significant surfaces
Significant surfaces are indicated preferably by drawings or by suitably marked samples. In
some cases, there can be different requirements for the finish on different parts of the
significant surface(s). Masking can be necessary to enable different requirements to be
achieved.
15.4.4 Thickness grade
Some guidance is given in clause 11.
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15.4.5 Surface preparation
ISO 7599 includes a surface preparation designation system.
15.4.6 Final dimensional tolerances
Anodizing leads to an increase in the dimensions of an article, which is equal to about 50% of
the coating thickness for each anodized surface.
15.5 Complaints
Any complaints by customers to anodizers should be made in writing. The anodizer shall
maintain a register of complaints which includes actions taken
15.6 Laboratory and testing apparatus
15.6.1 Laboratory
The anodizing plant shall have laboratory facilities.
15.6.2 Apparatus
15.6.2.1 General
Each apparatus shall conform to the requirements of the appropriate standard for the test
concerned. Each piece of apparatus shall be functional and have a data sheet showing the
apparatus identification number and calibration checks.
15.6.2.2 Apparatus for product testing
Each anodizing plant shall have at least two instruments for measuring thickness using the
eddy current method or one instrument for the eddy current method and one split-beam optical
microscope (9.2).
The anodizing plant shall have available apparatus for measuring wear resistance (9.6.2,
9.6.3, 9.6.5)
The anodizing plant shall have access to apparatus to carry out any other product tests
described in 15.8 that are required by the customer.
15.6.2.3 Apparatus for testing baths
If the anodizing line has one or more sealing baths, the anodizing plant laboratory shall have
a pH meter and two buffer solutions.
15.7 Product tests to be applied by the licensee
Some subclauses in this section are omitted on purpose.
15.7.1 Required tests
The licensee shall apply the following product quality tests depending on the products it
produces. See below for details.
• Thickness
• Visible defects
• Wear resistance
• Final dimensional tolerances
Additionally, the licensee shall apply any of the tests described below that are required by the
customer.
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If it is not possible to take and test specimens from the production lot because of the shape,
size or form of the product, the licensee may carry out tests on samples made of the same
alloy as the production lot and treated simultaneously with it. This shall be recorded in the
production control system.
The licensee shall have the standards specifying the tests that it applies. The standards are
identified in clause 4.
15.7.2 Thickness and dimensional tolerances
Thickness measurements shall be made using a method of 9.2.
Where a nominal thickness of up to 50 µm is specified, the average thickness shall not be
outside ± 20% of the nominal thickness. Where a nominal thickness over 50 µm is specified,
the average thickness shall not be outside ±10 µm of the nominal thickness.
The measurement of thickness or, where relevant, final dimensions, shall be dealt with in a lot
acceptance test.
15.7.4 Visible defects
Parts shall be examined visually in compliance with 9.4.1. The significant surface shall be
completely anodized. The visual appearance shall be substantially uniform without spalling,
blistering or powdery (burnt) areas. Crazing or microcracks are not normally a reason for
rejection.
15.7.7 Corrosion resistance
If required by the customer, the corrosion resistance shall be assessed using the neutral salt
spray test method of 9.5. The duration of the test shall be 336 hours.
After the test, a test piece with an anodic oxidation coating thickness of 50 μm shall not show
any corrosion pits except those within 1.5 mm of jigging marks or corners.
This test is only applicable to sealed anodic oxidation coatings.
15.7.9 Wear resistance
The wear resistance of anodic oxidation coatings shall be determined by using either the
abrasive wheel method of 9.6.2 or the abrasive jet method of 9.6.3. The selection of the
method and the procedure shall comply with ISO 10074. The Taber method of 9.6.5 may be
used only when it is specified.
The time between anodizing and testing shall be at least 24 h. During this period, the test
pieces shall be stored in the test environment.
The number of double strokes used in the abrasive wheel test shall be 800 to 100.
The test frequency shall be agreed by the licensee and the customer.
The relative mean specific abrasion resistance of the abrasive wheel and abrasive jet methods
shall be greater than 80%.
The mass loss of the Taber method shall not be greater than 15 mg.
15.7.10 Microhardness
If required by the customer, the Vickers microhardness of anodic oxidation coatings shall be
determined by using the method of 9.7. The test load shall be 0,49 N.
The test frequency and the acceptance criterion shall be agreed by the licensee and the
customer. In the absence of such an agreement, the following criteria shall apply. The
microhardness value, Hv 0,05, of coatings not thicker than 50 µm shall not be less than 400.
The microhardness value, Hv 0,05, of coatings thicker than 50 µm shall not be less than 350.
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15.7.13 Electrical breakdown potential
If required by the customer, the electrical breakdown potential shall be determined using the
method of 9.10.
The test frequency and the acceptance criterion shall be agreed by the licensee and the
customer. In the absence of such an agreement, anodic oxidation coatings 50 µm thick shall
have a minimum breakdown voltage of 1200 V. The value shall be the mean of ten
measurements.
15.7.15 Surface density
If required by the customer, the surface density shall be determined using the method of 9.12.
The test frequency and the acceptance criterion shall be agreed by the licensee and the
customer. In the absence of such an agreement, the surface density shall be at least 1100
mg/dm2 for a 50 µm thick coating or equivalent for coatings of other thicknesses.
15.7.17 Roughness
If required by the customer, the method, test frequency and acceptance criterion shall be
agreed by the licensee and the customer.
15.7.18 Service simulation tests
If required by the customer, anodized products shall be assessed using a test or tests specified
by the customer to simulate the service conditions. The test frequency and the acceptance
criterion shall be agreed by the licensee and the customer.
15.8 Requirements concerning processes
15.8.1 Anodizing
Anodizing shall be carried out using solutions based on sulfuric acid.
15.9 Methods for process control
15.9.1 Anodizing
Anodizing baths shall be analysed in accordance with the instructions of the supplier of any
anodizing additive. In the absence of such instructions, the analysis of free sulfuric acid and
dissolved aluminium shall be carried out. The analysis frequency shall be at least:
• once a day for each bath if three shifts are worked per day;
• once every two days for each bath if two eight-hour shifts are worked per day;
• once every three days for each bath if one eight-hour shift is worked per day.
Based on the results of the analysis the bath composition shall be adjusted accordingly.
The temperature of each anodizing bath shall be checked at regular intervals and at least
twice during every work shift when the line is in use. It shall be checked at the end of an
anodizing cycle.
15.9.2 Storage of products
Aluminium products shall be stored away from the anodizing facilities both before and after
anodizing. After anodizing, they shall be protected from condensation and dirt.
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15.10 Production control records
15.10.1 Control systems
The anodizing plant shall have a secure system for controlling production and its records shall
show at least the following information.
• The customer's name and address, order or serial number.
• The production date.
• The agreed coating thickness and the actual thickness measured (minimum and
maximum values of average thickness).
• Final dimensional tolerances
• The results of the wear resistance test.
• The results of all other tests required by the customer.
• Measures taken to remedy values not meeting the requirements.
The records shall include the following.
• The results of analyses and temperature monitoring of anodizing baths, and the
number of shifts worked.
• The product name and application of any proprietary chemicals or processes used.
All the information shall be readily accessible for the inspector.
15.10.2 Traceability
The licensee shall specify and maintain procedures to associate the production clearly with
the pertinent drawings, specifications or other documents during all phases of production,
delivery and assembly. Individual products, lots or batches must be identified unmistakably.
This identification shall be included in the control system records.
15.11 Inspections
15.11.1 General
The inspector carries out inspections as described in clause 8 with reference to the
requirements included here in 15.11. In order to avoid an unproductive inspection visit, it is
advisable that the plant notifies the appropriate body if it is concerned that sufficient material
for testing might not be available during certain periods.
15.11.2 Identification of parts passed by internal quality control
The licensee shall indicate to the Qualanod inspector which goods have passed the internal
quality control. Goods that are kept in stock ready for dispatch or packed shall be considered
to have passed the internal quality control.
The licensee shall clearly identify parts not covered by his licence for hard anodizing. The
inspector may seek verification of the type of anodizing by, for example, examining the written
agreement between the anodizer and his customer.
15.11.3 The product tests of an inspection
The following product tests can be carried out during an inspection.
• Coating thickness
• Final dimensions
The applicability to the products and the acceptance criteria are the same as those given in
15.7. Note that for the purposes of an inspection, all the tests have equal significance; the
concept of a referee test is not applicable.
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15.11.4 Processes
The inspector verifies that the processes are carried out in compliance with the requirements
of 15.8. He also verifies by observation that bath analyses are performed correctly.
If a licensee does not want a particular anodizing line to be included in the inspection, he shall
provide evidence to the inspector that it is not used for hard anodizing. Production control
records can provide such evidence.
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